CN103983439B - A kind of method that canopy is lengthened the life surely - Google Patents

Abstract

The invention belongs to aircraft fatigue field, relate to a kind of canopy Transparent Parts surely to lengthen the life complete method, it is characterized in that, comprise the steps: first, determine canopy typical mission section and flight data, second, canopy is carried out temperature computation and LOAD FOR, 3rd, establishment canopy temperature/loading spectrum, 4th, carry out canopy ground heating loading fatigue test, 5th, calculate canopy outfield tan by the sun the time and carry out canopy outfield degradation, 6th, ground heating loading fatigue test is proceeded after aging, 7th, formulate outfield canopy damage tolerance and check detailed rules and regulations, 8th, acoustic fatigue durability analysis is carried out by oil aircraft, 9th, provide canopy service life.The invention have the advantage that holonomic system establishes the system that canopy is lengthened the life surely, cover the whole fixed flow process lengthened the life of canopy and method, it is ensured that the use safety of canopy, significant, remarkable in economical benefits.

Description

A kind of method that canopy is lengthened the life surely

Technical field

The invention belongs to tired field, relate to a kind of method that canopy is lengthened the life surely.

Background technology

Canopy and windscreen renewal cost are higher, and the replacement cycle is longer, and once replacing seat hatchcover is saturating Bright part, then can cause aircraft to ground, and the life-span the most reasonably formulating canopy is extremely important 's.The canopy life-span was given simply by full-scale fatigue test in the past, the most safely and effectively The fault-tolerance formulating outfield canopy to ensure the use safety of canopy, fly for by oil Machine does not accounts for the noise impact on canopy fatigue life, and the present invention establishes a set of complete simultaneously The method surely lengthened the life of canopy become, defines canopy and surely lengthens the life system, can contain all The canopy of aircraft and newly grind canopy determine life-prolonging technique.Have great importance, simultaneously Remarkable in economical benefits.

Summary of the invention

It is an object of the invention to: propose a kind of method that canopy is lengthened the life surely, it is possible to comprehensively, be The formulating service life of canopy or canopy lengthened the life of system, it is ensured that the use of canopy Safety.

The technical scheme is that a kind of method that canopy is lengthened the life surely, it is characterised in that Comprise the steps:

First, determine canopy typical mission section and flight data；

Second, canopy is carried out temperature computation and LOAD FOR；

Temperature computation formula is:

Lucite is divided into n-layer:

$\frac{{\mathrm{dT}}_1}{dt}=\frac{h}{c\·r\·\frac{\mathrm{\δ}}{2(n-1)}}(T_{jb}-T_1)+\frac{2\mathrm{\λ}}{c\·r{\left(\frac{\mathrm{\δ}}{n-1}\right)}^2}(T_2-T_1)-\frac{c_o\·{\mathrm{\ϵ}}_o}{c\·r\frac{\mathrm{\δ}}{2(n-1)}}{\left(\frac{T_1}{100}\right)}^4$

$\frac{{\mathrm{dT}}_i}{dt}=\frac{\mathrm{\λ}}{c\·r{\left(\frac{\mathrm{\δ}}{n-1}\right)}^2}(T_{i+1}-2T_i+T_{i-1}),(2\≤i\≤n-1)$

$\frac{{\mathrm{dT}}_n}{dt}=\frac{2\mathrm{\λ}}{c\·r{\left(\frac{\mathrm{\δ}}{n-1}\right)}^2}(T_{n-1}-T_n)+\frac{2h^{\′}}{c\·r\frac{\mathrm{\δ}}{n-1}}(T_Z-T_n)$

In formula, each parameter is shown in Table:

Wherein the 1st layer is outer surface, and n-th layer is inner surface, and Tz is the sky pressing close to inner surface Gas-bearing formation temperature；

Use Euler's polygonal arc method solution above equation, i.e. can get temperature-time course；

Aerodynamic loading calculates and uses aerodynamics evaluation software to obtain, and supercharging load is pressed cockpit pressure and adjusted Pitch curve determines；

3rd, work out canopy temperature/loading spectrum

Temperature and the load history of calculating being mated, the principle of coupling is:

3) by the result of temperature computation, section is divided into high temperature section, middle temperature section, normal Temperature section and low temperature section, and mate load；

4) determine that load filters threshold value, choose the load more than threshold value as representative section Load；

4th, carry out canopy ground heating loading fatigue test

5th, calculate canopy outfield ageing time, and carry out canopy outfield degradation

6th, aging after proceed ground heating loading fatigue test

7th, formulate canopy Transparent Parts fault-tolerance and check detailed rules and regulations

Canopy Transparent Parts fault-tolerance formulating method is as follows:

9) the typical fault mode of canopy lucite is determined；

10) prefabricated organic glass stretching fatigue criteria sample, fault glass elements testpieces and Perspex test part after fault restoration

11) lucite degradation is carried out

12) apply aging after testpieces carry out fatigue property test

13) canopy fatigue details finite element analysis model is set up

14) canopy lucite stress spectra under fatigue load spectrum is calculated

15) use component fatigue performance test data that the canopy lucite life-span is estimated Calculate: estimation uses linear cumulative damage law to carry out；

Estimation uses linear cumulative damage law to carry out, and damage measurement formula is:

$D_i=\frac{n_i}{N_i}---\left(1\right)$

In formula: D_iFor damage

n_iCycle-index for section each in loading spectrum；

N_iFor the cycle-index in stress spectra counter structure S-N；

I is each section in corresponding loading spectrum.

Determine that estimated life is:

$T=\frac{T_{mb}}{f\·{\mathrm{\ΣD}}_i}---\left(2\right)$

In formula: f is the coefficient of dispersion；

T_mbFor canopy target life objective；

Canopy glass elements after being respectively adopted without defect, band defect and defect repair is tired Performance data carries out life estimate to canopy lucite, obtains the band organic glass of defect canopy Glass and repair rear canopy lucite relative to without under defect lucite fatigue life Fall rate, determines the life-span of different depth defect canopy lucite.

16) canopy glass fault-tolerance under target life objective is provided according to estimation result

Life Calculation result according to various lesion depths canopy lucites and index of aging Compare, such as T ＜ T_mbThen under this depth of defect, estimated life can not meet wanting of index of aging Ask, then need defect is placed under repair, thereby determine that the fault-tolerance of canopy lucite.

Combine flight progress according to the fault-tolerance formulated and formulate canopy inspection detailed rules and regulations.

8th, provide canopy service life

According to full-scale canopy heating and loading fatigue test, outfield degradation, acoustic fatigue longevity Life is analyzed, and provides the group of planes service life of canopy.

Preferably, carrying out during canopy determines service life, adding noise circumstance factor to seat The impact analysis in hatchcover life-span, comprises the steps:

1) establishment canopy glass acoustic loads spectrum；

2) element random vibration fatigue test is carried out；

3) canopy glass acoustic fatigue life estimate, provides the canopy glass life-span shadow of noise circumstance Ring conclusion.

The invention have the advantage that the mode that application test combines with analysis defines canopy fixed The process lengthened the life, the method meet conventional strength check theory, beneficially intensity engineer understand and Grasp.Whole procedures system is comprehensive, it is possible to contains whole canopy and determines longevity and the follow-up side lengthened the life Method, significant, remarkable in economical benefits.

Accompanying drawing explanation

Fig. 1 is that canopy is lengthened the life flow chart surely.

Fig. 2 is to formulate canopy fault-tolerance flow process.

Detailed description of the invention

Below by specific embodiment and combine accompanying drawing the present invention is made further details of retouching State.

Shown below is the example that certain canopy is lengthened the life surely.

First, determine canopy typical mission section and flight data

Investigation and analysis aircraft flight, train, take a flight test during whole flight outlines and flight cut open Face, by the analysis to thru-flight outline, determines the typical mission section of canopy.

The flight data that respectively rises and falls of this aircraft is analyzed, sorts out typical flight data, Including the time, highly, Mach number, the angle of attack.

Second, canopy is carried out temperature computation and LOAD FOR

According to flight section and flight data flight profile, mission profile each to canopy carry out temperature-time Between course calculate and load-time history calculate.

Each section purpose LOAD FOR result is carried out rain-flow counting, and carries out Oudin conversion, Oudin Conversion is carried out as follows:

P^Equivalent _yi=[P_{max i}(P_{max i}-P_{min i})]^1/2 n_{Y average}≥0

P^Equivalent _yi=[P_{min i}(P_{min i}-P_{max i})]^1/2 n_{Y average}＜ 0

Set up canopy details stress analysis model, according to LOAD FOR result, canopy is carried out Stress analysis, determines the load threshold value on life damage impact according to stress calculating results.

Material condition fatigue limit when lucite-25 DEG C, R=0.1 is 63.98, R=0 Time canopy lucite conditional fatigue limit be 59.63MPa, revised condition is tired The limit is for for 59.63 × 0.693=41.32MPa.

The stress produced when temperature is-25 DEG C, and load is 0.02MPa is 24MPa, and warm Degree for-25 DEG C, load be stress when 0 be 24.4MPa, less than conditional fatigue limit.

According to temperature profile statistical result, under a complete cold cycle, for once temperature Degree circulation, it can be considered that at low temperatures, selects this section maximum load as this temperature The load of degree circulation should be safe.

According to stress and breakdown diagnosis result, in the case of room temperature, select 0.025MPa conduct Load threshold value is content to retain sovereignty over a part of the country complete.At low temperatures, only select this section's purpose maximum load, Remaining side crops industry all amputates.

Apply for test is easy to load, room temperature load is converted to 2 progression load.Equivalence The conversion of equivalent number of times is carried out by following formula.

In formula:

N_dEquivalent number of times after conversion；

N_iLoad X at different levels_aiOccurrence number；

P_aiLoad values at different levels；

P_akThe load value of the conversion level determined；

The material constant that m calculates according to S-N curve.

S-N Curve can be expressed as S within the specific limits^m(m is material constant to N=C；C For constant).

Take 2 point on S-N curve, have:

${\left(\frac{S_1}{S_2}\right)}^m=\frac{N_2}{N_1},m=\frac{{\mathrm{lgN}}_2-{\mathrm{lgN}}_1}{{\mathrm{lgS}}_1-{\mathrm{lgS}}_2}$

Taking two point values is:

N₁=20000, S₁=37.34；N₂=5 × 10⁴, S₂=34.7

$m=\frac{{\mathrm{lgN}}_2-{\mathrm{lgN}}_1}{{\mathrm{lgS}}_1-{\mathrm{lgS}}_2}=12.27$

Subject under room temperature is carried out equivalent damage conversion.

3rd, work out canopy temperature/loading spectrum

Being a spectrum block with 1000 hours, the representative section after coupling is shown in Table.

Section coupling being had is adjusted, it is ensured that temperature loading spectrum integrity and be easy to test Time loading.

4th, carry out canopy ground heating loading fatigue test

Full-scale canopy is installed on special testing stand, carries out loading fatigue examination of heating Test, testing stand needs the Aerodynamic Heating of simultaneously analog capsule cabin exterior surface and supercharging load and gas The effect of dynamic loading.Testpieces installation on testing stand is carried out by drawing, does not allow to force peace Dress.

Test and carry out according to the canopy temperature loading spectrum of establishment.

5th, calculate canopy outfield ageing time and carry out canopy outfield degradation

According to aging field statistical data, monthly average between 1999～in March, 2006 to August Sunshine-duration sum is between 1500 hours～1700 hours.Tan by the sun 6 months and be equivalent to Hainan The ultraviolet light using for 1000 pilot time irradiates.

Within 24 hours in tanning by the sun, exposing, relative humidity examination is harsher.

Therefore, tan by the sun 6 months and can meet the requirement using for 1000 pilot time.

6th, aging after proceed ground heating loading fatigue test

After completing the aging light exposure test in outfield, reinstall to carry out on fatigue test board follow-up Heating and loading fatigue test.

7th, formulate outfield canopy fault-tolerance and check detailed rules and regulations

1) prefabricated canopy lucite tensile fatigue standard specimen, the test of fault glass elements Perspex test part after part and fault restoration

2) canopy glass degradation is carried out

According to the requirement in canopy service life, canopy glass test part is carried out aging examination Testing, ageing time is consistent with canopy target lifetime.

3) apply aging after testpieces carry out fatigue property test

Testpieces after aging is carried out tensile fatigue performance test, determine different defective form and Fatigue behaviour after depth of defect canopy glass is aging.

Different depth scratches lucite room temperature tensile fatigue conditional fatigue limit and is shown in Table.

Different depth scratches lucite room temperature tensile fatigue conditional fatigue limit

From table, during scratch depth 0.4mm, lucite fatigue behaviour is decreased significantly.

4) canopy fatigue detail analysis model is set up

Being built by canopy lucite as volume elements, through-thickness is divided into 10 layers, and will calculate Thermograde be applied on canopy lucite.Supercharging load in passenger cabin has been applied to The inner surface of machine glass, aerodynamic loading is applied to the outer surface of lucite, and at two side skeletons The upper connection applied between constraint simulation skeleton and mouth frame.

5) canopy lucite stress spectra under fatigue load spectrum is calculated

Different sections in using canopy fatigue detail analysis model to compose temperature loading are carried out Stress analysis, the stress spectra obtaining correspondence is shown in Table.

Canopy stress spectra

6) use component fatigue performance test data that the canopy lucite life-span is estimated

The S-N Curve of test is modified by the construction features according to canopy, revises system Number is shown in Table.

Table lucite S-N curve amendment coefficient

Using revised S-N curve is under 1200 pilot time loading spectrums to the corresponding life-span Canopy lucite carries out life estimate, and it is 6 that life estimate chooses the coefficient of dispersion, different deep Degree scratches the accumulated damage of lucite and is shown in Table:

Table different depth scratches the accumulated damage of lucite

Life-span of canopy lucite without scratching isPilot time；

The life-span of the canopy lucite of scratch depth 0.3mm isFly Row hour；

The life-span of the canopy lucite of scratch depth 0.4mm isFly Row hour.

7) canopy glass fault-tolerance under target life objective is provided according to estimation result

Target life objective is disclosure satisfy that according to the scuffing that estimation result scratch depth is below 0.3mm The requirement at 1200 pilot time, scratch depth 0.4mm then fatigue behaviour declines relatively big, no The demand of target life objective can be met.

8th, carried out acoustic fatigue durability analysis by oil aircraft

1) canopy glass acoustic loads spectrum

According to flight outline and typical mission section, with flight data for being originally inputted, carry out The calculating of 250 hours loading spectrums.

Actual measurement acoustic loads according to each state of flight and to the statistics of state of flight, merging, Finally obtain state of flight, overall sound pressure level and one equivalence of respective seat hatchcover and rise and fall (50min) The middle state of flight time, work out canopy glass acoustic loads spectrum.

Acoustic loads spectrum use flight rise and fall (50min) be a spectrum block.

2) element random vibration fatigue test

Carry out the test of canopy glass elements random vibration S-N curve, counted for the acoustic fatigue life-span Calculate and foundation is provided.

3) canopy glass acoustic fatigue life estimate

Canopy is a doubly-curved shell, according to canopy glass and skeleton connection, during calculating Take non-complete hinged boundary condition clamped, non-.According to vibration, noise fatigue analysis principle, meter The calculation canopy glass acoustic fatigue life-span was 1867 pilot time.In noise fatigue durability analysis, The acoustic load of each state all takes maximum load value, and acoustic fatigue lifetime results is the most conservative.Therefore Providing canopy under its actual noise load effect born, its acoustic fatigue life-span is more than 1800 Service life at pilot time.

9th, provide canopy service life

Comprehensive full-scale canopy heating and loading fatigue test, degradation, acoustic fatigue life-span divide Analysis, provides the service life of canopy, thin in conjunction with the line fault-tolerance formulated and inspection Then, it is ensured that canopy use safety in lifetime.

Claims (2)

1. the method that a canopy is lengthened the life surely, it is characterised in that comprise the steps:

First, determine canopy typical mission section and flight data；

Second, canopy is carried out temperature computation and LOAD FOR；

Temperature computation formula is:

Lucite is divided into n-layer:

$\frac{{\mathrm{dT}}_1}{dt}=\frac{h}{c\·r\·\frac{\mathrm{\δ}}{2(n-1)}}(T_{jb}-T_1)+\frac{2\mathrm{\λ}}{c\·r{\left(\frac{\mathrm{\δ}}{n-1}\right)}^2}(T_2-T_1)-\frac{c_o\·{\mathrm{\ϵ}}_o}{c\·r\frac{\mathrm{\δ}}{2(n-1)}}{\left(\frac{T_1}{100}\right)}^4$

$\frac{{\mathrm{dT}}_i}{dt}=\frac{\mathrm{\λ}}{c\·r{\left(\frac{\mathrm{\δ}}{n-1}\right)}^2}(T_{i+1}-2T_i+T_{i-1}),(2\≤i\≤n-1)$

$\frac{{\mathrm{dT}}_n}{dt}=\frac{2\mathrm{\λ}}{c\·r{\left(\frac{\mathrm{\δ}}{n-1}\right)}^2}(T_{n-1}-T_n)+\frac{2h^{\′}}{c\·r\frac{\mathrm{\δ}}{n-1}}(T_Z-T_n)$

In formula, each parameter is shown in Table:

Wherein the 1st layer is outer surface, and n-th layer is inner surface, and Tz is the sky pressing close to inner surface Gas-bearing formation temperature；

Use Euler's polygonal arc method solution above equation, i.e. can get temperature-time course；

Aerodynamic loading calculates and uses aerodynamics evaluation software to obtain, and supercharging load is pressed cockpit pressure and adjusted Pitch curve determines；

3rd, work out canopy temperature/loading spectrum

Temperature and the load history of calculating being mated, the principle of coupling is:

1) by the result of temperature computation, section is divided into high temperature section, middle temperature section, normal Temperature section and low temperature section, and mate load；

2) determine that load filters threshold value, choose the load more than threshold value as representative section Load；

4th, carry out canopy ground heating loading fatigue test

5th, calculate canopy outfield ageing time, and carry out canopy outfield degradation

6th, aging after proceed ground heating loading fatigue test

7th, formulate canopy Transparent Parts fault-tolerance and check detailed rules and regulations

Canopy Transparent Parts fault-tolerance formulating method is as follows:

1) the typical fault mode of canopy lucite is determined；

2) prefabricated organic glass stretching fatigue criteria sample, fault glass elements testpieces and Perspex test part after fault restoration

3) lucite degradation is carried out

4) apply aging after testpieces carry out fatigue property test

5) canopy fatigue details finite element analysis model is set up

6) canopy lucite stress spectra under fatigue load spectrum is calculated

7) use component fatigue performance test data that the canopy lucite life-span is estimated Calculate: estimation uses linear cumulative damage law to carry out；

Estimation uses linear cumulative damage law to carry out, and damage measurement formula is:

$D_i=\frac{n_i}{N_i}---\left(1\right)$

In formula: D_iFor damage

n_iCycle-index for section each in loading spectrum；

N_iFor the cycle-index in stress spectra counter structure S-N；

I is each section in corresponding loading spectrum；

Determine that estimated life is:

$T=\frac{T_{mb}}{f\·{\mathrm{\ΣD}}_i}---\left(2\right)$

In formula: f is the coefficient of dispersion；

T_mbFor canopy target life objective；

Canopy glass elements after being respectively adopted without defect, band defect and defect repair is tired Performance data carries out life estimate to canopy lucite, obtains the band organic glass of defect canopy Glass and repair rear canopy lucite relative to without under defect lucite fatigue life Fall rate, determines the life-span of different depth defect canopy lucite；

8) canopy glass fault-tolerance under target life objective is provided according to estimation result

Life Calculation result according to various lesion depths canopy lucites and index of aging Compare, such as T ＜ T_mbThen under this depth of defect, estimated life can not meet wanting of index of aging Ask, then need defect is placed under repair, thereby determine that the fault-tolerance of canopy lucite；

Combine flight progress according to the fault-tolerance formulated and formulate canopy inspection detailed rules and regulations；

8th, provide canopy service life

According to full-scale canopy heating and loading fatigue test, outfield degradation, acoustic fatigue longevity Life is analyzed, and provides the group of planes service life of canopy.

The method that canopy the most according to claim 1 is lengthened the life surely, it is characterised in that entering During row canopy determines service life, add the noise circumstance factor shadow to the canopy life-span Ring and analyze, comprise the steps:

1) establishment canopy glass acoustic loads spectrum；

2) element random vibration fatigue test is carried out；

3) canopy glass acoustic fatigue life estimate, provides the canopy glass life-span shadow of noise circumstance Ring conclusion.