CN104007351A - Method for determining spacecraft electronic assembly heat cycle test scheme - Google Patents

Abstract

A method for determining a thermal cycle test scheme of an electronic assembly of a spacecraft comprises the following steps: Step 1: determination of an alternative scheme for the thermal cycle test; step 2: calculation of the temperature difference ΔT ₁ of each component of the electronic assembly of the spacecraft under the condition of the thermal cycle test; 3: Effectiveness analysis of spacecraft electronic components thermal cycle test; Step 4: Calculation of temperature difference ΔT ₂ of each component of spacecraft electronic components under normal working conditions; Step 5: Damage analysis of spacecraft electronic components thermal cycle test; Step 6: Aerospace Normal working damage analysis of electronic components of spacecraft; Step 7: Acceptability analysis of thermal cycle test of electronic components of spacecraft; Step 8: Finalized thermal cycle test plan. This method can avoid over-testing and under-testing of spacecraft electronic components caused by thermal cycle test scheme, and reduce the application risk of spacecraft electronic components in aerospace engineering.

Description

A Method for Determining Thermal Cycle Test Scheme of Spacecraft Electronic Components

(1) Technical field:

The invention relates to a method for determining a thermal cycle test scheme of an electronic component of a spacecraft, which is suitable for evaluating whether various thermal cycle test schemes adopted by different electronic components of a spacecraft are reasonable and effective, and is dedicated to avoiding the impact of the thermal cycle test scheme on the electronic component of a spacecraft. The method of causing over-test and under-test and reducing the application risk of spacecraft electronic components in aerospace engineering belongs to the technical field of spacecraft thermal cycle test. the

(two) background technology:

In the development process of spacecraft electronic product components, reasonable and effective thermal cycle tests can screen out potential early failures of spacecraft electronic components and ensure the reliability and service life of spacecraft electronic components. the

In current engineering practice, the thermal cycle test of spacecraft electronic components is mainly carried out in accordance with GJB 1027-2005 "Test Requirements for Vehicles, Upper Stages, and Spacecrafts". However, GJB 1027-2005 adopts the same test requirements for different spacecraft electronic product components, and lacks effective pertinence for the defect characteristics and working profiles of specific spacecraft electronic product components. In actual engineering, there are also cases where electronic components of spacecraft that pass thermal cycle tests fail within the design life cycle. the

On the other hand, the thermal cycle test program is usually analyzed, only considering the effectiveness of the thermal cycle test program, that is, the ratio of the number of faults exposed in the test to the total number of faults, without considering the unnecessary damage of the product due to the overstress of the test. To analyze and determine the thermal cycle test plan, it is necessary to comprehensively consider the under-test and over-test risks of the thermal cycle test on the electronic components of the spacecraft, so as to obtain a reasonable and effective thermal cycle test plan. the

(3) Contents of the invention:

1. Purpose: The purpose of the present invention is to provide a method for determining a thermal cycle test scheme for spacecraft electronic components. For specific spacecraft electronic components, under-test and over-test are considered comprehensively to determine a reasonable and effective thermal cycle test scheme. the

2. Technical solution: The present invention takes the thermal cycle test alternative as the research object, and uses the Coffin-Manson thermal fatigue life theory and Miner Based on the linear cumulative damage theory, based on the validity analysis and acceptability analysis of the thermal cycle test, a method for determining the thermal cycle test program of the spacecraft electronic components is established, which includes the following steps:

Step 1: Determination of thermal cycle test alternatives: According to the design requirements of spacecraft electronic components, initially determine the thermal cycle test alternatives;

Step 2: Calculation of the temperature difference _ΔT1 of each component of the spacecraft electronic component under the thermal cycle test conditions: collect relevant information of the spacecraft electronic component, use commercial software to establish a digital prototype of the spacecraft electronic component, and use the thermal cycle test equipment determined in step 1 According to the selected scheme, the temperature difference ΔT ₁ of each component of the spacecraft electronic component is calculated under the thermal cycle test condition;

Step 3: Effectiveness analysis of thermal cycle test of spacecraft electronic components: Determine the effective area S ₁ of solder joints of early failure components of spacecraft electronic components, and calculate the temperature difference ΔT ₁ of each component of spacecraft electronic components under the conditions of step 2 thermal cycle test. The shear strain Δγ ₁ of the solder joint of the early failure device of the spacecraft electronic component, using the Coffin-Manson thermal fatigue model, calculates the thermal fatigue life N _f1 of the early failure device of the spacecraft electronic component, and judges whether the early failure device of the spacecraft electronic component can survive the thermal cycle test Screening out, that is, whether the cycle number N of the thermal cycle test alternative is greater than the thermal fatigue life N _f1 of the early failure devices of the spacecraft electronic components, count the number of early failure devices and the total number of early failure devices in the spacecraft electronic components, Calculate the validity of the thermal cycle test of the spacecraft electronic components. If the validity of the thermal cycle test is 100%, go to step 4. If the validity of the thermal cycle test is not 100%, tighten the conditions and go to step 2 again;

Step 4: Calculation of the temperature difference _ΔT2 of each component of the spacecraft electronic component under normal working conditions: According to the design requirements of the spacecraft electronic component, determine the normal operating temperature profile of the spacecraft electronic component, and use commercial software and the spacecraft electronic component established in step 2 Digital prototype, calculate the temperature difference ΔT ₂ of each component of the spacecraft electronic components under normal working conditions;

Step 5: Thermal cycle test damage analysis of spacecraft electronic components: Determine the effective area S ₂ of solder joints of normal components of spacecraft electronic components, and calculate _the spacecraft electronic The shear strain Δγ ₂ of the solder joint of the normal components of the component is calculated by using the Coffin-Manson thermal fatigue model to calculate the thermal fatigue life N _f2 of the normal component of the spacecraft electronic component, and the test damage rate D ₁ of the normal component of the spacecraft electronic component in the thermal cycle test can be obtained;

Step 6: Normal working damage analysis of spacecraft electronic components: According to the effective area S ₂ of normal solder joints of spacecraft electronic components determined in step 5 and the temperature difference ΔT ₂ of each component of spacecraft electronic components under normal working conditions determined in step 4, calculate The shear strain Δγ ₃ of the solder joint of the normal component of the spacecraft electronic component is calculated using the Coffin-Manson thermal fatigue model to calculate the thermal fatigue life N _f3 of the normal component of the spacecraft electronic component, which can meet the design life and meet the normal operating conditions of the spacecraft electronic component. Device damage rate D ₂ ;

Step 7: Acceptability analysis of the thermal cycle test of spacecraft electronic components: Based on the test damage rate D ₁ obtained in step 5 and the working damage rate D ₂ obtained in step 6, calculate the full life cycle damage rate D of normal components of spacecraft electronic components , to determine whether there is a life-cycle damage rate D>1 of normal components in the electronic components of the spacecraft, if not, go to step 8, if it exists, relax the conditions, and go to step 2 again;

Step 8: The final thermal cycle test plan is an effective and reasonable thermal cycle test plan for specific spacecraft electronic components. the

Among them, the thermal cycle test alternatives described in step 1 include the maximum temperature T ₁ , the minimum temperature T ₂ , the maximum temperature immersion time t ₁ , the minimum temperature immersion time t ₂ , and the temperature cycle number N of the thermal cycle test. , temperature change rate v, etc.

Thermal cycle test alternatives can refer to domestic and foreign standards such as GJB 1027-2005 "Test Requirements for Vehicles, Upper Stages, and Space Vehicles" or MIL-HDBK-340A "Test Requirement for Launch, Upper-stage, and Space Vehicles", such as Table 1 shows. the

Among them, the information related to the electronic components of the spacecraft described in step 2 includes the outline parameters of the PCB board, the layer information of the PCB, the part number of each component of the electronic components of the spacecraft, the packaging form, the material, the location, the size, and the power consumption. and other relevant information. The commercial software required for modeling includes PWA, Flotherm, etc. Calculate the maximum temperature T' ₁ and the minimum temperature T' ₂ of the shell temperature of each component of the spacecraft electronic component under the conditions of the highest temperature T ₁ and the lowest temperature T ₂ of the thermal cycle test, and obtain the spacecraft electronic component under the condition of the thermal cycle test The temperature difference ΔT ₁ of each device, the calculation formula is as follows

ΔT ₁ =T' ₁ -T' ₂ .

Table 1 Thermal Cycle Test Alternatives

Among them, the effective area _S1 of solder joints of early failure devices of spacecraft electronic components mentioned in step 3 can be obtained from the actual measurement statistics or engineering experience of the defective solder joint area.

Under the condition of thermal cycle test, the shear strain Δγ ₁ of the solder joint of the early failure device of the spacecraft electronic component is calculated as follows

${\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.38</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

In the formula, Δγ ₁ is the shear strain of the solder joint of the early failure device under the thermal cycle test condition; K _D is the bending stiffness of the solder joint, the unit is N/mm; S ₁ is the effective area of the solder joint of the early failure device, the unit is mm ² ; h is the height of the solder joint, in mm; ΔαLT _c is the expansion of the device, in mm, and ΔαLT _s is the expansion of the circuit board, in mm. The calculation formula is as follows

$\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;</span>}{\mathrm{<span\; class="notranslate">\; LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; cx</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; cy</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}$

$\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;</span>}{\mathrm{<span\; class="notranslate">\; LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; sx</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; sy</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}$

In the formula, L _x is the maximum spacing of solder joints or the span of the solder joint array in the x direction, in mm; L _y is the maximum spacing of solder joints or the span of the solder joint array in the y direction, in mm; α _cx is the x direction α _cy is the thermal expansion coefficient of the device in the y direction, the unit is ppm/°C; α _sx is the thermal expansion coefficient of the circuit board in the x direction, the unit is ppm/°C; α _sy is The thermal expansion coefficient of the circuit board in the y direction, in ppm/°C.

Use the Coffin-Manson thermal fatigue model to calculate the thermal fatigue life N _f1 of early failure devices of spacecraft electronic components, and the calculation formula is as follows

${\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}<span\; class="notranslate">\; )</span>}^{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}}}$

In the formula, N _f1 is the thermal fatigue life of early failure devices under thermal cycle test conditions; Δγ ₁ is the shear strain of solder joints of early failure devices under thermal cycle test conditions; ε' _f is the fatigue ductility coefficient, usually 2ε' _f ≈ 0.65; c is the fatigue ductility index, the calculation formula is as follows

$\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.442</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1.74</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 360</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>$

In the formula, T _m is the average temperature of the solder joint during the test period, in °C; t _D is the maximum temperature immersion time, in min.

Judging whether the early failure devices of spacecraft electronic components can be screened out in the thermal cycle test, that is, whether the cycle number N of the thermal cycle test alternative is greater than the thermal fatigue life N _f1 of early failure devices of spacecraft electronic components, and statistics of spacecraft electronic components The number m of early failure devices and the total number M of early failure devices can be screened out, and the validity E of the thermal cycle test of spacecraft electronic components can be calculated. The calculation formula is as follows

$\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$

If the validity of the thermal cycle test is 100%, proceed to step 4, if the validity of the thermal cycle test is not 100%, then tighten the conditions, appropriately increase the maximum temperature _T1 or reduce the minimum temperature _T2 or increase the temperature For cycle number N, repeat step 2.

Among them, the normal operating temperature profile of the spacecraft electronic components mentioned in step 4 is determined by the design requirements of the spacecraft electronic components, mainly including the highest temperature T ₃ , the lowest temperature T ₄ , the highest temperature immersion time t ₃ , Minimum temperature immersion time t ₄ , temperature change rate v, number of temperature cycles N ₁ experienced in the design life cycle, etc.

Use the commercial software PWA, Flotherm, etc. and the digital prototype of the spacecraft electronic components established in step 2 to calculate the maximum temperature T of the shell temperature of each component of the spacecraft electronic components under the conditions of the highest temperature _T3 and the lowest temperature _T4 in normal use ' ₃ and the lowest temperature T' ₄ , to obtain the temperature difference ΔT ₂ of the electronic components of the spacecraft in normal operation, the calculation formula is as follows

ΔT ₂ =T' ₃ -T' ₄

Wherein, the effective area _S2 of the solder joint of the normal device of the spacecraft electronic component mentioned in step 5 can be obtained from the actual measurement statistics of the effective area of the normal solder joint or the device manual.

Under the thermal cycle test conditions, the shear strain Δγ ₂ of the normal component solder joints of the spacecraft electronic components, the calculation formula is as follows

${\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.38</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

In the formula, Δγ ₂ is the shear strain of solder joints of normal devices under thermal cycle test conditions; K _D is the bending stiffness of solder joints, in N/mm; S ₂ is the effective area of solder joints in normal devices, in mm ² ; h is Solder joint height, unit is mm; ΔαLT _c is the expansion of the device, ΔαLT _s is the expansion of the circuit board, the calculation formula is as follows

$\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;</span>}{\mathrm{<span\; class="notranslate">\; LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; cx</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; cy</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}$

$\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;</span>}{\mathrm{<span\; class="notranslate">\; LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; sx</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; sy</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}$

In the formula, L _x is the maximum spacing of solder joints or the span of the solder joint array in the x direction, and the unit is in; L _y is the maximum spacing of solder joints or the span of the solder joint array in the y direction, and the unit is in; α _cx is the x direction The thermal expansion coefficient of the upper device, the unit is ppm/℃; α _cy is the thermal expansion coefficient of the device in the y direction, the unit is ppm/℃; α _sx is the thermal expansion coefficient of the circuit board in the x direction, the unit is ppm/℃; α _sy is The thermal expansion coefficient of the circuit board in the y direction, in ppm/°C.

Using the Coffin-Manson thermal fatigue model, calculate the thermal fatigue life N _f2 of the normal components of the spacecraft electronic components under the thermal cycle test conditions, the calculation formula is as follows

${\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}<span\; class="notranslate">\; )</span>}^{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}}}$

In the formula, N _f2 is the thermal fatigue life of normal devices under thermal cycle test conditions; Δγ ₂ is the shear strain of solder joints of normal devices under thermal cycle test conditions; ε' _f is the fatigue ductility coefficient, usually 2ε' _f ≈ 0.65; c is Fatigue ductility index, the calculation formula is as follows

$\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.442</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1.74</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 360</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>$

In the formula, T _m is the average temperature of the solder joint during the test period, in °C; t _D is the maximum temperature immersion time, in min.

Calculate the test damage rate D ₁ of the normal components of the spacecraft electronic components in the thermal cycle test, the calculation formula is as follows

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; N</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}$

Among them, under the normal operating conditions of the spacecraft described in step 6, the shear strain Δγ ₃ of the solder joint of the spacecraft electronic component is normal, and the calculation formula is as follows

${\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.38</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

In the formula, Δγ ₃ is the shear strain of solder joints of normal devices under normal working conditions; K _D is the bending stiffness of solder joints, the unit is N/mm; S ₂ is the effective area of solder joints of normal devices, the unit is mm ² ; h is the solder joint Point height, unit is mm; ΔαLT _c is the expansion of the device, ΔαLT _s is the expansion of the circuit board, the calculation formula is as follows

$\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;</span>}{\mathrm{<span\; class="notranslate">\; LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; cx</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; cy</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}$

$\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;</span>}{\mathrm{<span\; class="notranslate">\; LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; =</span>\sqrt{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; sx</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; sy</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; \&Delta;T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}$

In the formula, L _x is the maximum spacing of solder joints or the span of the solder joint array in the x direction, and the unit is in; L _y is the maximum spacing of solder joints or the span of the solder joint array in the y direction, and the unit is in; α _cx is the x direction α _cy is the thermal expansion coefficient of the device in the y direction, the unit is ppm/°C; α _sx is the thermal expansion coefficient of the circuit board in the x direction, the unit is ppm/°C; α _sy is The thermal expansion coefficient of the circuit board in the y direction, in ppm/°C.

Using the Coffin-Manson thermal fatigue model, calculate the thermal fatigue life N _f3 of the normal components of the spacecraft electronic components under normal working conditions, the calculation formula is as follows

${\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}<span\; class="notranslate">\; )</span>}^{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}}}$

In the formula, N _f3 is the thermal fatigue life of normal devices under normal working conditions; Δγ ₃ is the shear strain of solder joints of normal devices under normal working conditions; ε' _f is the fatigue ductility coefficient, usually 2ε' _f ≈ 0.65; c is the fatigue ductility index, the calculation formula is as follows

$\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.442</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1.74</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 360</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>$

In the formula, T _m is the average temperature of the solder joint under normal working conditions, in °C; t _D is the maximum temperature immersion time under normal working conditions, in min.

Calculate the test damage rate D ₂ of the normal components of the spacecraft electronic components under normal operation, the calculation formula is as follows

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}}$

Among them, the damage rate D of the normal device life cycle of aerospace electronic components described in step 7 is calculated as follows

D＝D ₁ +D ₂

Judging whether there is a life cycle damage rate D>1 of normal components in the electronic components of the spacecraft, if not, go to step 8, if it exists, relax the conditions, appropriately reduce the maximum temperature T ₁ or increase the minimum temperature T ₂ or reduce the temperature cycle number N, and repeat step 2.

Among them, the thermal cycle test scheme finally determined in step 8 is a scheme that meets the requirements of thermal cycle test validity and thermal cycle test acceptability, and the final output results are the maximum temperature T ₁ , minimum temperature T ₂ , Maximum temperature immersion time t ₁ , minimum temperature immersion time t ₂ , temperature cycle number N, temperature change rate v.

The invention provides a method for determining a thermal cycle test scheme of an electronic component of a spacecraft, and its advantages mainly include: the present invention is aimed at a specific electronic component of a spacecraft, and analyzes the effectiveness and thermal cycle of the thermal cycle test of the electronic component of a spacecraft. The acceptability of the test is more targeted and reasonable. Based on the Coffin-Manson thermal fatigue life theory and Miner's linear cumulative damage theory, the present invention obtains an effective and reasonable thermal cycle test scheme through calculation and analysis, has the advantages of strong operability, saving test costs, etc., and can conveniently and quickly formulate aerospace electronic Product thermal cycle test program. the

(4) Description of drawings:

Figure 1 is the implementation flow of the method for determining the thermal cycle test scheme of spacecraft electronic components

The labels and symbols in the figure are explained as follows:

T ₁ is the maximum temperature of thermal cycle test

_T2 is the minimum temperature of thermal cycle test

_t1 is the maximum temperature immersion time of thermal cycle test

_t2 is the minimum temperature immersion time of thermal cycle test

N is the temperature cycle number of thermal cycle test

v is the temperature change rate of the thermal cycle test

_T'1 is the maximum temperature of the shell temperature of each component of the spacecraft electronic component under the thermal cycle test condition

_T'2 is the minimum temperature of the shell temperature of each component of the spacecraft electronic components under the thermal cycle test conditions

ΔT ₁ is the temperature difference between the components of the spacecraft electronic components under the thermal cycle test conditions

S ₁ is the effective area of the solder joint of the early failure device of the spacecraft electronic component

Δγ ₁ is the shear strain of the early failure device solder joint of the spacecraft electronic component under the condition of thermal cycle test

K _D is the bending stiffness of the solder joint

h is the height of solder joint

ΔαLT _c is the expansion of the device

ΔαLT _s is the expansion of the circuit board

L _x is the maximum spacing of solder joints or the span of solder joint array in the x direction

L _y is the maximum spacing of solder joints or the span of solder joint array in the y direction

α _cx is the thermal expansion coefficient of the device in the x direction

α _cy is the thermal expansion coefficient of the device in the y direction

α _sx is the thermal expansion coefficient of the circuit board in the x direction

α _sy is the thermal expansion coefficient of the circuit board in the y direction

N _f1 is the thermal fatigue life of early failure devices of spacecraft electronic components

Δγ ₁ is the shear strain of solder joints of early failure devices under thermal cycle test conditions

ε' _f is the fatigue ductility coefficient

T _m is the average temperature of the solder joint during the test period

t _D is the maximum temperature immersion time

m is the number of components that can screen out early failures in the electronic components of the spacecraft

M is the total number of early failure devices in the spacecraft electronic components

E is the validity of thermal cycle test of spacecraft electronic components

T ₃ is the highest temperature in normal work

T ₄ is the lowest temperature in normal operation

_t3 is the maximum temperature immersion time in normal work

_t4 is the minimum temperature immersion time in normal work

v is the temperature change rate in normal operation

N ₁ is the number of temperature cycles experienced in the design life cycle

_T'3 is the maximum temperature of the shell temperature of each component of the spacecraft electronic components during normal operation

_T'4 is the minimum temperature of the shell temperature of each component of the spacecraft electronic components in normal operation

ΔT ₂ is the temperature difference between the electronic components of the spacecraft during normal operation

S ₂ is the effective area of solder joints of normal components of spacecraft electronic components

Δγ ₂ is the shear strain of normal device solder joints of spacecraft electronic components under thermal cycle test conditions

S ₂ is the effective area of the normal device solder joint

N _f2 is the thermal fatigue life of normal components of spacecraft electronic components under thermal cycle test conditions

D ₁ is the test damage rate of normal components of spacecraft electronic components

Δγ ₃ is the shear strain of the solder joints of the normal components of the spacecraft electronic components in normal operation

N _f3 is the thermal fatigue life of normal components of spacecraft electronic components in normal operation

_D2 is the working damage rate of the normal components of the spacecraft electronic components in normal work

D is the life cycle damage rate of normal components of aerospace electronic components

(5) Specific implementation methods:

In the following, the method for determining the thermal cycle test scheme of the spacecraft electronic component for a specific spacecraft electronic component according to the present invention will be described in detail in combination with specific implementation cases. the

Case: Attitude and orbit control engine parameter acquisition board applied to spacecraft

The present invention takes an attitude-orbit control engine parameter acquisition board applied to a spacecraft as an example to illustrate a method for determining a thermal cycle test scheme of a spacecraft electronic component for a specific spacecraft electronic component. the

The information and application requirements of the attitude control engine parameter acquisition board are as follows:

(1) Attitude and Orbit Control Engine Parameter Acquisition Board: This parameter acquisition board is used for a certain type of synchronous orbit communication satellite, located in the propulsion cabin of the satellite, with a size of 96mm×86mm×1.53mm, a total power consumption of 1.4W, and includes 8 types There are 11 electronic components, and the list of components is shown in Table 4. the

(2) Application requirements: The design life of the synchronous orbit communication satellite is 15 years, and the temperature cycle is 24 hours, of which, the temperature change time is 6 hours, and the temperature immersion time is 6 hours. In general, the ambient temperature of the propulsion cabin is -10 to +40°C, and the application requirements for the temperature environment when the acquisition board is working are shown in Table 2. the

Table 2 Parameters related to the working environment temperature of the acquisition board

According to the flow chart in Figure 1, the specific steps of the method are as follows:

Step 1: Determine the alternatives for the thermal cycle test. Preliminarily determine that the maximum temperature _T1 of the thermal cycle test is 60°C, the minimum temperature _T2 is -25°C, the maximum temperature immersion time _t1 is 60min, the minimum temperature immersion time is 60min, and the temperature The cycle number N is 25, and the temperature change rate v is 4°C/min.

Step 2: Collect information about spacecraft electronic components. The size of the PCB board is 96mm×86mm×1.53mm. The layer information of the PCB board is shown in Table 3. Material, location, size, power consumption and other relevant information are shown in Table 4. the

Table 3 PCB board layer information

Laminate ply material Ply thickness (mm) laminated metal material Laminate metal content (%) top floor epoxyF 0.06 Cu 23.17 level one FR4 0.43 Cu 2.56 power epoxyF 0.06 Cu 95.64 Second floor FR4 0.43 Cu 2.56 GND epoxyF 0.06 Cu 96.12 the third floor FR4 0.43 Cu 2.56 bottom layer epoxyF 0.06 Cu 11.23

Table 4 Attitude and Orbit Control Engine Parameter Acquisition Board Device List

Using commercial software such as PWA and Flotherm, calculate the maximum temperature _T'1 and the minimum temperature _T'2 of the shell temperature of the electronic components of the spacecraft in the thermal cycle test, the highest temperature _T1 and the lowest temperature _T2 , respectively, and obtain the thermal cycle test conditions The temperature difference ΔT ₁ of each component of the electronic components of the lower spacecraft is shown in Table 5.

Table 5 Temperature difference of various components of spacecraft electronic components under thermal cycle test conditions

Step 3: Collect relevant parameters and calculate the expansion of each device and its circuit board, as shown in Table 6. Using relevant formulas and early failure related parameters of spacecraft electronic components, calculate the shear strain Δγ ₁ of solder joints of early failure components of spacecraft electronic components under thermal cycle test conditions, as shown in Table 7. Using the Coffin-Manson thermal fatigue model, calculate the thermal fatigue life N _f1 of early failure devices of aerospace electronic components, as shown in Table 8.

Table 6 Expansion of various components and circuit boards of spacecraft electronic components under thermal cycle test conditions

Table 7 Shear strain of early failure device solder joints of spacecraft electronic components under thermal cycle test conditions

serial number bit number ΔT ₁ (°C) ΔαLT _c ΔαLT _s K _D S ₁ h Δγ ₁ 1 C101 84.9656 0.0098 0.0126 540000000 0.306 0.2 0.1965 2 C102 84.9493 0.0098 0.0126 35600000 0.0306 0.2 0.1295 3 C103 84.93637 0.0098 0.0126 35600000 0.0306 0.2 0.1295 4 D101 84.89719 0.0216 0.0611 1970 0.025893 0.25 0.2684 5 D102 84.87448 0.0208 0.0587 2400 0.025893 0.25 0.2772 6 D103 84.95754 0.0041 0.0117 34000 0.00135 0.2 0.1522 7 D104 84.96317 0.0100 0.0117 13300000 0.00135 0.2 0.1491 8 D105 84.96311 0.0136 0.0158 10700000 0.003906 0.145 0.1603 9 D106 84.9197 0.0098 0.0276 5800 0.0045 0.25 0.1875 10 D107 84.94361 0.0064 0.0181 106000 0.01593 0.25 0.1807

the serial number bit number ΔT ₁ (°C) ΔαLT _c ΔαLT _s K _D S ₁ h Δγ ₁ 11 D108 84.90089 0.0208 0.0587 2300 0.025893 0.25 0.2656

Table 8 Thermal cycle test effectiveness analysis

serial number bit number ΔT ₁ (°C) T _m t _D c 2ε' _f Δγ ₁ N _f1 <N 1 C101 84.9656 17.8157 60 -0.418831 0.65 0.1965 8.7 yes 2 C102 84.9493 17.96507 60 -0.41892 0.65 0.1295 23.5 yes 3 C103 84.93637 18.0966 60 -0.418999 0.65 0.1295 23.5 yes 4 D101 84.89719 18.74909 60 -0.419391 0.65 0.2684 4.1 yes 5 D102 84.87448 18.98552 60 -0.419532 0.65 0.2772 3.8 yes 6 D103 84.95754 18.17347 60 -0.419045 0.65 0.1522 16.0 yes 7 D104 84.96317 18.11839 60 -0.419012 0.65 0.1491 16.8 yes 8 D105 84.96311 18.13628 60 -0.419023 0.65 0.1603 14.1 yes 9 D106 84.9197 18.79857 60 -0.41942 0.65 0.1875 9.7 yes 10 D107 84.94361 18.63799 60 -0.419324 0.65 0.1807 10.6 yes 11 D108 84.90089 18.73037 60 -0.419379 0.65 0.2656 4.2 yes

It can be seen from Table 8 that the number m of early failure devices that can be screened out in spacecraft electronic components is 11, and the total number of early failure devices M is 11, so the effectiveness E of the thermal cycle test of spacecraft electronic components is 100%. the

Since the validity E of the thermal cycle test of the spacecraft electronic components is 100%, proceed to step 4. the

Step 4: The normal operating temperature profile of spacecraft electronic components is determined by the design requirements of spacecraft electronic components, mainly including the maximum temperature _T3 in normal operation is 50°C, the minimum temperature _T4 is -10°C, and the maximum temperature immersion time _t3 is 6 hours, the minimum temperature immersion time _t4 is 6 hours, the temperature change rate v is 10°C/hour, and the number of temperature cycles _N1 experienced in the design life cycle is 5475 times.

Use PWA, Flotherm and other commercial software to calculate the highest temperature _T'3 and the lowest temperature _T'4 of the shell temperature of the electronic components of the spacecraft in normal operation, respectively, to obtain the maximum temperature _T'3 and the minimum temperature _T'4 of the spacecraft in normal operation The temperature difference ΔT ₂ of each component of the electronic component is shown in Table 9.

Table 9 Temperature difference of various components of spacecraft electronic components during normal operation

Step 5: Collect relevant parameters and calculate the expansion of each device and its circuit board, as shown in Table 6. Using relevant formulas and related parameters of normal spacecraft electronic components, calculate the shear strain Δγ ₂ of solder joints of spacecraft electronic components under thermal cycle test conditions, as shown in Table 10. Using the Coffin-Manson thermal fatigue model, calculate the thermal fatigue life N _f2 of normal components of aerospace electronic components under thermal cycle test conditions, and calculate the test damage rate D ₁ of normal components of aerospace electronic components in thermal cycle tests, as shown in Table 8.

Table 10 Shear strain of early failure device solder joints of spacecraft electronic components under thermal cycle test conditions

serial number bit number ΔT ₁ (°C) ΔαLT _c ΔαLT _s K _D S ₂ h Δγ ₂ 1 C101 84.9656 0.0098 0.0126 540000000 1.02 0.2 0.0590 2 C102 84.9493 0.0098 0.0126 35600000 1.02 0.2 0.0039 3 C103 84.93637 0.0098 0.0126 35600000 1.02 0.2 0.0039 4 D101 84.89719 0.0216 0.0611 1970 0.3699 0.25 0.0188 5 D102 84.87448 0.0208 0.0587 2400 0.3699 0.25 0.0194 6 D103 84.95754 0.0041 0.0117 34000 0.09 0.2 0.0023 7 D104 84.96317 0.01 0.0117 13300000 0.09 0.2 0.0022 8 D105 84.96311 0.0136 0.0158 10700000 0.1302 0.145 0.0048 9 D106 84.9197 0.0098 0.0276 5800 0.09 0.25 0.0094 10 D107 84.94361 0.0038 0.0106 106000 0.531 0.25 0.0054 11 D108 84.90089 0.0122 0.0346 2300 0.3699 0.25 0.0186

Table 11 Test damage rate of normal components of spacecraft electronic components in thermal cycle test

serial number bit number ΔT ₁ (°C) T _m t _D c 2ε' _f Δγ _{2 f2} D ₁ 1 C101 84.9656 17.8157 60 -0.418831 0.65 0.0590 154.7 0.1616 2 C102 84.9493 17.96507 60 -0.41892 0.65 0.0039 101185.2 0.0002 3 C103 84.93637 18.0966 60 -0.418999 0.65 0.0039 101014.5 0.0002 4 D101 84.89719 18.74909 60 -0.419391 0.65 0.0188 2340.6 0.0107 5 D102 84.87448 18.98552 60 -0.419532 0.65 0.0194 2335.4 0.0107 6 D103 84.95754 18.17347 60 -0.419045 0.65 0.0023 375345.5 0.0001 7 D104 84.96317 18.11839 60 -0.419012 0.65 0.0022 375746.2 0.0001 8 D105 84.96311 18.13628 60 -0.419023 0.65 0.0048 61094.0 0.0004 9 D106 84.9197 18.79857 60 -0.41942 0.65 0.0094 12289.9 0.0020 10 D107 84.94361 18.63799 60 -0.419324 0.65 0.0054 44872.4 0.0006 11 D108 84.90089 18.73037 60 -0.419379 0.65 0.0186 2340.8 0.0107

Step 6: According to the relevant parameters of the normal solder joints of the spacecraft electronic components and the temperature difference ΔT ₂ of the components of the spacecraft electronic components under normal working conditions, calculate the thermal expansion of the spacecraft electronic components and the shear strain Δγ of the normal component solder joints under normal working conditions ₃ , as shown in Table 12 and Table 13. Using the Coffin-Manson thermal fatigue model, calculate the thermal fatigue life N _f3 of the normal components of the spacecraft electronic components under normal working conditions, and calculate the working damage rate D ₂ of the normal components of the spacecraft electronic components under normal working conditions, as shown in Table 14 .

Table 12 Thermal expansion of electronic components of spacecraft under normal working conditions

Table 13 Shear strain of normal component solder joints of spacecraft electronic components under normal working conditions

serial number bit number ΔT ₁ (°C) ΔαLT _c ΔαLT _s K _D S ₂ h Δγ ₃ 1 C101 50.01978 0.0057 0.0074 540000000 1.02 0.2 0.0075 2 C102 50.01195 0.0057 0.0074 35600000 1.02 0.2 0.0005 3 C103 50.00648 0.0057 0.0074 35600000 1.02 0.2 0.0005 4 D101 50.06008 0.0128 0.0360 1970 0.3699 0.25 0.0023 5 D102 50.01005 0.0123 0.0346 2400 0.3699 0.25 0.0023 6 D103 49.76564 0.0024 0.0068 34000 0.09 0.2 0.0003 7 D104 49.76512 0.0059 0.0068 13300000 0.09 0.2 0.0002 8 D105 51.02652 0.0082 0.0095 10700000 0.1302 0.145 0.0007 9 D106 50.16632 0.0058 0.0163 5800 0.09 0.25 0.0012 10 D107 49.86146 0.0038 0.0106 106000 0.531 0.25 0.0006 11 D108 49.98466 0.0122 0.0346 2300 0.3699 0.25 0.0022

Table 14 Working damage rate of normal components of spacecraft electronic components under normal working conditions

serial number bit number ΔT ₁ (°C) T _m t _D c 2ε' _f Δγ ₃ N _{f3 D2} 1 C101 50.01978 15.34074 60 -0.417346 0.65 0.0075 22304.9 0.2455 2 C102 50.01195 15.493395 60 -0.417437 0.65 0.0005 14935709.4 0.0004 3 C103 50.00648 15.6279 60 -0.417518 0.65 0.0005 14910884.6 0.0004 4 D101 50.06008 16.32446 60 -0.417936 0.65 0.0023 382475.0 0.0143 5 D102 50.01005 16.545985 60 -0.418069 0.65 0.0023 379769.5 0.0144 6 D103 49.76564 15.57503 60 -0.417486 0.65 0.0003 72000112.4 0.0001 7 D104 49.76512 15.51722 60 -0.417451 0.65 0.0002 80130252.0 0.0001 8 D105 51.02652 16.16586 60 -0.417841 0.65 0.0007 6366164.9 0.0009 9 D106 50.16632 16.41722 60 -0.417991 0.65 0.0012 1921589.0 0.0028 10 D107 49.86146 16.09365 60 -0.417797 0.65 0.0006 7691387.6 0.0007 11 D108 49.98466 16.26635 60 -0.417901 0.65 0.0022 383406.9 0.0143

Step 7: Acceptability analysis of thermal cycle test of spacecraft electronic components: Calculate the life cycle damage rate D of normal components of spacecraft electronic components based on the test damage rate D ₁ obtained in step 5 and the working damage rate D ₂ obtained in step 6 , to determine whether the life-cycle damage rate D of normal components in spacecraft electronic components is > 1, as shown in Table 15. Since the life cycle damage rate D>1 of normal components does not exist in the electronic components of the spacecraft, proceed to step 8.

Table 15 Life cycle damage rate D of normal components of spacecraft electronic components

serial number bit number D _{1 D2} D. Whether > 1 1 C101 0.1616 0.2455 0.4071 no 2 C102 0.0002 0.0004 0.0006 no 3 C103 0.0002 0.0004 0.0006 no 4 D101 0.0107 0.0143 0.0250 no 5 D102 0.0107 0.0144 0.0251 no 6 D103 0.0001 0.0001 0.0001 no 7 D104 0.0001 0.0001 0.0001 no 8 D105 0.0004 0.0009 0.0013 no 9 D106 0.0020 0.0028 0.0049 no 10 D107 0.0006 0.0007 0.0013 no 11 D108 0.0107 0.0143 0.0250 no

Step 8: The thermal cycle test plan finally determined is an effective and reasonable thermal cycle test plan for the parameter acquisition board, as shown in Table 16. the

Table 16 Thermal Cycle Test Scheme

Claims (9)

1. A method for analyzing and determining a thermal cycle test scheme of a spacecraft electronic component, characterized in that: thermal analysis, Coffin-Manson model and full life cycle theory are used to analyze thermal cycle test validity and acceptability of thermal cycle tests. The validity and damage of the cyclic test plan on the specified spacecraft electronic components, according to the flow of this method, iterative judgment, and finally determine the appropriate spacecraft electronic component thermal cycle test plan, the specific steps of the method are as follows: Step 1: Determination of thermal cycle test alternatives; Step 2: Calculate the temperature difference ΔT ₁ of each component of the spacecraft electronic component under the thermal cycle test condition; Step 3: Analyze the validity of the thermal cycle test of spacecraft electronic components. If the validity of the thermal cycle test is 100%, proceed to step 4. If the validity of the thermal cycle test is not 100%, tighten the conditions and repeat step 2; Step 4: Calculate the temperature difference ΔT ₂ of each component of the spacecraft electronic components under normal working conditions; Step 5: Damage analysis of spacecraft electronic components thermal cycle test; Step 6: Damage analysis of spacecraft electronic components during normal operation; Step 7: Acceptability analysis of the thermal cycle test of spacecraft electronic components, to determine whether there is a damage rate of normal components in the entire life cycle of spacecraft electronic components D>1, if not, go to step 8, if it exists, relax the conditions , repeat step 2; Step 8: The final thermal cycle test plan is an effective and reasonable thermal cycle test plan for specific spacecraft electronic components. 2. The determination of thermal cycle test alternatives according to claim 1, characterized in that: the main parameters of the thermal cycle test program in step 2 are the highest temperature T ₁ , the lowest temperature T ₂ , the highest temperature immersion Time t ₁ , minimum temperature immersion time t ₂ , temperature cycle number N, temperature change rate v. 3. According to the calculation of the temperature difference _ΔT of each component of the spacecraft electronic assembly under the thermal cycle test condition of claim 1, it is characterized in that: in step 2, the use of relevant software is used to calculate the temperature of each component of the aerospace electronic product assembly. The shell temperature at each temperature level of the thermal cycle test is obtained, and the shell temperature difference ΔT ₁ of each component of the aerospace electronic product assembly is obtained. 4. The validity analysis of the thermal cycle test of the spacecraft electronic assembly according to claim 1, characterized in that: (1) In step 3, the effective area _S1 of solder joints of early failure devices of spacecraft electronic components can be obtained by the actual measurement statistics or engineering experience of the defective solder joint area; (2) Under the thermal cycle test conditions described in step 3, the early failure of the electronic components of the spacecraft is all injection of device failure; (3) Calculation formula for shear strain _Δγ1 of solder joints of early failure devices of spacecraft electronic components under the thermal cycle test conditions described in step 3 ${\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.38</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ In the formula, Δγ ₁ is the shear strain of the solder joint of the early failure device under the thermal cycle test condition, K _D is the bending stiffness of the solder joint, the unit is N/mm, S ₁ is the effective area of the solder joint of the early failure device, the unit is mm ² , h is the height of the solder joint in mm; (4) Calculation formula for the effectiveness E of the spacecraft electronic component thermal cycle test described in step 3 $\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$ In the formula, E is the effectiveness of thermal cycle test of spacecraft electronic components, m is the number of early failure devices in spacecraft electronic components that can be screened out, and M is the total number of early failure devices in spacecraft electronic components; (5) If the validity of the heat cycle test is 100% as described in step 3, then proceed to step 4, if the validity of the heat cycle test is not 100%, then tighten the conditions and appropriately increase the maximum temperature _T1 or decrease Lower the minimum temperature _T2 or increase the number N of temperature cycles, and repeat step 2. 5. The temperature difference ΔT ₂ of each component of the spacecraft electronic assembly under normal working conditions according to claim 1, characterized in that: in step 4, use relevant software to calculate the normal working conditions of each component of the aerospace electronic product assembly The shell temperature at each temperature level, and the shell temperature difference ΔT ₂ of each component of the aerospace electronic product assembly is obtained. 6. The thermal cycle test damage analysis of spacecraft electronic components according to claim 1, characterized in that: (1) The effective area _S2 of the solder joint of the normal device of the spacecraft electronic component described in step 5 can be obtained from the actual measurement statistics of the effective area of the normal solder joint or the device manual; (2) Under the thermal cycle test conditions described in step 5, the formula for calculating the shear strain Δγ ₂ of the normal component solder joints of the spacecraft electronic components ${\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.38</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ In the formula, Δγ ₂ is the shear strain of the solder joint of the early failure device under the thermal cycle test condition, K _D is the bending stiffness of the solder joint, the unit is N/mm, S ₂ is the effective area of the normal device solder joint, the unit is mm ² , h is the height of the solder joint, in mm; (3) Calculation formula for the test damage rate _D1 of the thermal cycle test described in step 5 to the normal components of the spacecraft electronic components ${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; N</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}$ In the formula, _D1 is the test damage rate of the normal components of the spacecraft electronic components in the thermal cycle test, N is the temperature cycle number of the thermal cycle test, and N _f2 is the thermal fatigue life of the normal components under the thermal cycle test conditions. 7. The normal work damage analysis of the spacecraft electronic assembly according to claim 1, characterized in that: (1) Calculation formula for shear strain Δγ ₃ of solder joints of normal components of spacecraft electronic components under normal working conditions of spacecraft described in step 6 ${\mathrm{<span\; class="notranslate">\; \&Delta;\&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1.38</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&Delta;\&alpha;LT</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ In the formula, Δγ ₃ is the shear strain of the solder joint of the early failure device under the thermal cycle test condition, K _D is the bending stiffness of the solder joint, the unit is N/mm, S ₂ is the effective area of the normal device solder joint, the unit is mm ² , h is the height of the solder joint, in mm; (2) Calculation formula for the test damage rate _D2 of the normal work of the spacecraft electronic components described in step 6 ${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}}$ In the formula, D ₂ is the test damage rate of normal components of spacecraft electronic components under normal operation, N ₁ is the number of temperature cycles experienced in the design life cycle, and N _f3 is the thermal fatigue life of normal components under normal working conditions. 8. The acceptability analysis of thermal cycle test of spacecraft electronic components according to claim 1, characterized in that: (1) Calculation method for the damage rate D of the whole life cycle of the normal components of the spacecraft electronic components mentioned in step 7 D＝D ₁ +D ₂ In the formula, D is the life-cycle damage rate of the normal components of the spacecraft electronic components, D ₁ is the test damage rate of the normal components of the spacecraft electronic components in the thermal cycle test, and D ₂ is the test of the normal components of the spacecraft electronic components. damage rate; (2) In step 7, judge whether there is a life-cycle damage rate D>1 of normal components in the electronic components of the spacecraft. If not, go to step 8. If it exists, relax the conditions and appropriately reduce the maximum Temperature T ₁ or increase the minimum temperature T ₂ or reduce the temperature cycle number N, and repeat step 2. 9. The final thermal cycle test scheme according to claim 1, characterized in that: the final output result in step 8 is the maximum temperature T ₁ , the minimum temperature T ₂ , and the maximum temperature immersion time of the thermal cycle test scheme t ₁ , minimum temperature immersion time t ₂ , temperature cycle number N, temperature change rate v.