CN103308723A - Product service life rapid test method based on physical model - Google Patents

Abstract

A product service life rapid test method based on a physical model comprises the steps of determining an equivalent environment profile; determining acceleration test conditions; determining an upper quality specification limit of the test; and determining a plurality of groups of sampling plans (n, c) under the given reliability and user risk. According to the method, the degradation physical model and acceleration tests are combined, so that forming of service life rapid test schemes of products of different types can be effectively guided, and whether the batch of products can meet service life index requirements under specified utilization conditions and environment conditions is tested within a short time. The stability rapid test method for product performance parameters is provided through the performance parameter physical model, so that the test sample size and test time can be saved, and research and development costs can be reduced; and by means of the acceleration test method, product batch production test time can be greatly shortened, and test procedures can be simplified.

Description

A kind of life of product method for quickly detecting based on physical model

Technical field

The invention provides a kind of life of product method for quickly detecting based on physical model, particularly relate to a kind of life-span method for quickly detecting based on degeneration physical model and accelerated test, belong to the fail-test technical field.

Background technology

Life of product can use performance parameter and defined threshold as sign.Product with degenerative character requires its performance parameter to satisfy at the appointed time and changes in the specialized range, needs to carry out the index of aging examination before dispatching from the factory.It is tight to face the product development cycle, and expense is controlled demanding situation, and in order to improve test efficiency, shorten the test period, to reduce testing expenses, the accelerated test technology becomes very important developing direction of fail-test technical field.Can this invention be based on the accelerated test technology based on the life of product method for quickly detecting of physical model and check out this batch products satisfy the index of aging requirement of particular product performance parameters under regulation service condition and environmental baseline in the short period of time.By new to looking into of prior art, also do not carry out the research of life of product check aspect based on parameter degeneration physical model both at home and abroad.

Summary of the invention

The object of the present invention is to provide a kind of life of product method for quickly detecting based on physical model, it is a kind of life of product method for quickly detecting of degenerate physical model and accelerated test, can effectively instruct the life-span quick test scheme that forms dissimilar products, thereby check out this batch products can satisfy index of aging requirement under regulation service condition and environmental baseline in the short period of time.

The present invention realizes by the following technical solutions, a kind of life of product method for quickly detecting based on physical model of the present invention, and its step is as follows:

Step 1: determine equivalent environment section

A. choose the degeneration physical model of product parameters, this degeneration physical model characterizes performance parameter amount of degradation and environmental stress and time relation, its functional form can be expressed as △ D=f (S, t);

B. choose the environmental stress section that product stands in life cycle, this section comprises environmental stress type, stress level and each stress level action time;

C. according to the degeneration physical model of parameter, the environmental stress section in the life cycle is carried out the equivalence conversion, equivalence is the environmental stress section under the normal stress level, determines the equivalent lifetime t under the normal stress level _Eq

Step 2: determine the accelerated test condition

A. the environmental stress section that stands according to product in the life cycle is determined accelerated test stress types and level;

B. determine speedup factor according to degeneration physical model and the following definitions of parameter;

Speedup factor is defined as: if product is accelerating stress level S _iWith the horizontal S of normal stress ₀Down, when performance parameter reached identical amount of degradation, the needed time was respectively t _iAnd t ₀, then claim

AF _i,0=t ₀/t _i (1)

For accelerating stress level S _iWith respect to the horizontal S of normal stress ₀Speedup factor.

C. determine the pick test time under the acceleration environment.

The pick test time under the acceleration environment is the equivalent lifetime t under the normal stress level _EqWith speedup factor AF _{I, 0}Ratio, can calculate by following formula:

$t_{\mathrm{in}}=\frac{t_{\mathrm{eq}}}{{\mathrm{AF}}_{i,0}}$ (2)

Calculate the speedup factor of the relative normal stress level of acceleration environment according to the life of product index request;

Step 3: the standard limit of improving quality of determining check

A. store the variance Changing Pattern that data are determined product parameters according to the outfield, calculate the variance of parameter equivalent during the life-span

B. calculate the standard limit of improving quality of check according to 3 σ principles.

1) utilizes pick test time corresponding parameters variable quantity under the degeneration physical model calculating acceleration environment of parameter

2) calculate the standard limit of checking of improving quality according to 3 σ principles

$\mathrm{UL}={\widehat{\mathrm{\μ}}}_t+3{\widehat{\mathrm{\σ}}}_t$ (3)

Step 4: determine under given fiduciary level and user's risk many groups sampling plan (n, c)

A. determine the acceptance number c in the sampling plan

Suppose from a collection of product to be checked to appoint and get n product and under acceleration environment, carry out timing truncation accelerated test, arrive pick test time t _InIn time, stop to test, and is located at [0, t _In] interior product failure r, the regulation acceptance number is c.

According to above-mentioned hypothesis, a product is at [0, t _In] in fiduciary level be R (t), under given user's risk β and fiduciary level R (t), determine acceptance number c according to following formula:

$\underset{r=0}{\overset{c}{\mathrm{\Σ}}}\left(\begin{array}{c}n\\ r\end{array}\right){[1-R\left(t\right)]}^r{\left[R\left(t\right)\right]}^{n-r}=\mathrm{\β}$ (4)

B. determine sampling inspection scheme

Decision making by following rule:

1) when r≤c, receives this batch product;

2) as r〉during c, reject this batch product.

For given fiduciary level R (t) and user's risk β, can make Q-percentile life sampling plan (n, c).More than one of this kind scheme possibility can be selected a use in a plurality of schemes.

Wherein, carry out the equivalence conversion at the environmental stress section with in the life cycle described in the step 1, determine the equivalent lifetime t under the normal stress level _Eq, can adopt following steps:

A. except the environmental stress section under the normal stress level, the environmental stress section under other stress level need calculate the parameter amount of degradation △ D under other each stress level respectively according to the degeneration physical model of parameter _i, and comprehensively obtain total amount of degradation of other each stress level

K is the stress level number;

B. the function of degeneration physical model is got contraryly, the calculating parameter amount of degradation reaches △ D _tThe time, be equivalent to the loss time t under the normal stress level _Og=f ^-1(△ D _t, S ₀);

C. calculate the equivalent lifetime t of environmental stress section under the normal stress level in the life cycle _Eq=t _Og+ t _No, t wherein _NoBe the action time under the normal stress level.

Wherein, described in the step 2 according to life cycle in the environmental stress section that stands of product determine accelerated test stress types and level, can adopt following steps:

A. the stress types in the environmental stress section that product stands in the combing life cycle, common stress types has temperature and vibration;

B. according to strenuous test result or the definite stress limit level that keeps the mechanism unanimity of engineering experience, the stress level of choosing in the accelerated test condition is higher than the normal stress level so, but can not be higher than the stress limit level.

The present invention has the following advantages:

1. the present invention utilizes performance parameter degeneration physical model to provide the method for quickly detecting of particular product performance parameters stability, can save test sample amount and test period, reduces R﹠D costs;

2. the present invention utilizes accelerated test method, can shorten product greatly and criticize proving time, the reduced inspection program of producing.

Description of drawings

Fig. 1 is the inventive method process flow diagram.

Fig. 2 is actual environment stress section of the present invention.

Embodiment

The present invention is described in further detail below in conjunction with drawings and Examples.

Following examples are to be that research object is implemented according to flow process as shown in Figure 1 with the quartz flexible accelerometer, finally determine accelerometer performance parameter stability quick test scheme.Specific as follows:

Step 1: determine equivalent environment section

A. choose the degeneration physical model of accelerometer parameter, this degeneration physical model characterizes performance parameter amount of degradation and environmental stress and time relation;

Accelerometer performance parameter constant multiplier with the physical model that temperature and time changes is:

$\frac{{\mathrm{\ΔK}}_1}{K_1}=({0.152e}^{-\frac{2704.701}{T}}+0.081e^{-\frac{2987.713}{T}}+0.060e^{-\frac{3053.967}{T}})t^{0.48}$ (5)

Wherein, the unit of T is K; The unit of t is the moon.

B. be chosen at the environmental stress section that product stands in the life cycle, this section comprises environmental stress type, stress level and each stress level action time;

Be mainly storage environment in the accelerometer life cycle, its environmental stress section is referring to shown in Figure 2, and for normal temperature was stored 22 months down for 25 ℃, open-air temperature was placed 2 months down for 45 ℃.

C. according to the degeneration physical model of parameter, the environmental stress section in the life cycle is carried out the equivalence conversion, equivalence is the environmental stress section under the normal stress level, determines the equivalent lifetime t under the normal stress level _Eq

Placing 2 months constant multiplier parameter variable quantities down for 45 ℃ according to the open-air temperature of accelerometer constant multiplier degeneration physical model formula (5) calculating is 57.9ppm, is equivalent to the parameter variable quantity of storing 6.8 months down at 25 ℃.

$\frac{{\mathrm{\ΔK}}_1}{K_1}={(0.152e^{-\frac{2704.701}{(45+273)}}+0.081e^{-\frac{2987.713}{(45+273)}}+0.060e^{-\frac{3053.967}{(45+273)}})}^{*}{2}^{0.48}=57.9\mathrm{ppm}$

Therefore, the actual environment stress section equivalence that stands under storage requirement of accelerometer is 25 ℃ and stored 28.8 months down.

Step 2: determine the accelerated test condition

A. the environmental stress section that stands according to product in the life cycle is determined accelerated test stress types and level;

The main environment stress that accelerometer stands under storage requirement is temperature, and the high temperature limit of having determined the maintenance mechanism unanimity of accelerometer by strenuous test is 90 ℃, determine that thus accelerated test stress is temperature stress, accelerated test condition stress level is selected 80 ℃.

B. determine speedup factor according to degeneration physical model and the following definitions of parameter;

Speedup factor is defined as: if product is accelerating stress level S _iWith the horizontal S of normal stress ₀Down, when performance parameter reached identical amount of degradation, the needed time was respectively t _iAnd t ₀, then claim

AF _i,0=t ₀/t _i

For accelerating stress level S _iWith respect to the horizontal S of normal stress ₀Speedup factor.

Accelerometer requires 2 years internal graticule factors of storage life to change and is no more than 150ppm under given storage requirement, and then can obtain accelerometer according to the degeneration physical model calculating is t in the storage life under 80 ℃ of the high temperature _{80 ℃}=2.373 months, the storage life under 25 ℃ was t _{25 ℃}=49.32 months.Determine that according to the degeneration physical model of accelerometer constant multiplier 80 ℃ of speedup factors with respect to 25 ℃ of normal temperatures of high temperature are

C. determine the pick test time under the acceleration environment.

The equivalent lifetime of constant multiplier under 25 ℃ of normal stress levels is 28.8 months, and constant multiplier is 20.78 in 80 ℃ of speedup factors with respect to 25 ℃ of normal temperatures of high temperature, so the pick test time under 80 ℃ of acceleration environments of high temperature is

$t_{\mathrm{in}}=\frac{28.8\×30\×24}{20.78}=998h$

Step 3: the standard limit of improving quality of determining check

A. store the variance Changing Pattern that data are determined product parameters according to the outfield, calculate the variance of parameter equivalent during the life-span

According to the constant multiplier Changing Pattern of 25 ℃ of following samples of accelerometer outfield storage, the variance Changing Pattern of constant multiplier under 25 ℃ is as can be known:

σ ²=0.0795×(1+t) ^1.369

Wherein t is period of storage, and unit is the sky.

Calculate the variance of constant multiplier equivalent lifetime in the time of 28.8 months according to formula

B. calculate the standard limit of improving quality of check according to 3 σ principles.

1) utilizes 80 ℃ of following t of degeneration physical model calculating of parameter _InCorresponding parameters variable quantity during=998h

${\widehat{\mathrm{\μ}}}_t=116\mathrm{ppm};$

2) calculating the standard of checking of improving quality according to 3 σ principles is limited to

$\mathrm{UL}={\widehat{\mathrm{\μ}}}_t+3{\widehat{\mathrm{\σ}}}_t=203\mathrm{ppm}$

Step 4: determine under given fiduciary level and user's risk many groups sampling plan (n, c)

A. determine the acceptance number c in the sampling plan;

Suppose from a collection of product to be checked to appoint and get n product and under acceleration environment, carry out timing truncation accelerated test, arrive pick test time t _InIn time, stop to test, and is located at [0, t _In] interior product failure r, the regulation acceptance number is c.

According to above-mentioned hypothesis, a product is at [0, t _In] in fiduciary level be R (t), under given user's risk β and fiduciary level R (t), determine acceptance number c according to following formula:

$\underset{r=0}{\overset{c}{\mathrm{\Σ}}}\left(\begin{array}{c}n\\ r\end{array}\right){[1-R\left(t\right)]}^r{\left[R\left(t\right)\right]}^{n-r}=\mathrm{\β}$ (6)

B. determine sampling inspection scheme.

Decision making by following rule:

1) when r≤c, receives this batch product;

2) as r〉during c, reject this batch product.

For given fiduciary level R (t) and user's risk β, can make Q-percentile life sampling plan (n, c).More than one of this kind scheme possibility can be selected a use in a plurality of schemes.

By above-mentioned supposition as can be known, an accelerometer is at [0, t _In] in fiduciary level be R (t), so n accelerometer is at [0, t _In] interior failure number r obeys binomial distribution, according to formula (6) can calculate many groups sampling plan under given fiduciary level R (t) and the user's risk β (n, c).Provided fiduciary level R=0.9 in the table 1,0.95, user's risk is respectively β=0.1,0.2,0.3, and acceptance number c is respectively c=0, the minimum sample drawn amount of correspondence under 1,2 situation.

Table 1R=0.9,0.95, β=0.1,0.2,0.3 acceptance number c=0, the smallest sample amount under 1,2 situation

Manufacturer chooses fiduciary level according to the qualified situation of the present sampling of accelerometer and acceptable sample drawn amount from table 1 be 0.9, and user's risk is 0.2 o'clock sampling plan (16,0).Comprehensively providing accelerometer storage life quick test scheme is:

From an inspection lot, appoint and get 16 accelerometers and carry out 80 ℃ of constant temperature accelerated test 998h, the constant multiplier variable quantity of all accelerometers all is no more than 203ppm, then think and can receive the index of aging requirement that accelerometer satisfied 2 years this batch accelerometer at this moment, otherwise reject this batch accelerometer.

Physical significance such as the following table of quoting letter among the present invention illustrate:

Claims (3)

1. life of product method for quickly detecting based on physical model, it is characterized in that: this method step is as follows:

Step 1: determine equivalent environment section

A. choose the degeneration physical model of product parameters, this degeneration physical model characterizes performance parameter amount of degradation and environmental stress and time relation, its functional form be expressed as △ D=f (S, t);

B. choose the environmental stress section that product stands in life cycle, this section comprises environmental stress type, stress level and each stress level action time;

C. according to the degeneration physical model of parameter, the environmental stress section in the life cycle is carried out the equivalence conversion, equivalence is the environmental stress section under the normal stress level, determines the equivalent lifetime t under the normal stress level _Eq

Step 2: determine the accelerated test condition

A. the environmental stress section that stands according to product in the life cycle is determined accelerated test stress types and level;

B. determine speedup factor according to degeneration physical model and the following definitions of parameter;

Speedup factor is defined as: if product is accelerating stress level S _iWith the horizontal S of normal stress ₀Down, when performance parameter reached identical amount of degradation, the needed time was respectively t _iAnd t ₀, then claim

AF _i,0=t ₀/t _i (1)

For accelerating stress level S _iWith respect to the horizontal S of normal stress ₀Speedup factor;

C. determine the pick test time under the acceleration environment;

The pick test time under the acceleration environment is the equivalent lifetime t under the normal stress level _EqWith speedup factor AF _{I, 0}Ratio, calculate by following formula:

$t_{\mathrm{in}}=\frac{t_{\mathrm{in}}}{{\mathrm{AF}}_{i,0}}$ (2)

Calculate the speedup factor of the relative normal stress level of acceleration environment according to the life of product index request;

Step 3: the standard limit of improving quality of determining check

A. store the variance Changing Pattern that data are determined product parameters according to the outfield, calculate the variance of parameter equivalent during the life-span

B. calculate the standard limit of improving quality of check according to 3 σ principles:

1) utilizes pick test time corresponding parameters variable quantity under the degeneration physical model calculating acceleration environment of parameter

2) calculate the standard limit of checking of improving quality according to 3 σ principles

$\mathrm{UL}={\widehat{\mathrm{\μ}}}_t+3{\widehat{\mathrm{\σ}}}_t$ (3)

Step 4: determine under given fiduciary level and user's risk many groups sampling plan (n, c)

A. determine the acceptance number c in the sampling plan

Suppose from a collection of product to be checked to appoint and get n product and under acceleration environment, carry out timing truncation accelerated test, arrive pick test time t _InIn time, stop to test, and is located at [0, t _In] interior product failure r, the regulation acceptance number is c;

According to above-mentioned hypothesis, a product is at [0, t _In] in fiduciary level be R (t), under given user's risk β and fiduciary level R (t), determine acceptance number c according to following formula:

$\underset{r=0}{\overset{c}{\mathrm{\Σ}}}\left(\begin{array}{c}n\\ r\end{array}\right){[1-R\left(t\right)]}^r{\left[R\left(t\right)\right]}^{n-r}=\mathrm{\β}$ (4)

B. determine sampling inspection scheme

Decision making by following rule:

1) when r≤c, receives this batch product;

2) as r〉during c, reject this batch product;

For given fiduciary level R (t) and user's risk β, make Q-percentile life sampling plan (n, c);

More than one of this kind scheme possibility is selected a use in a plurality of schemes.

2. a kind of life of product method for quickly detecting based on physical model according to claim 1 is characterized in that:

Carry out the equivalence conversion at the environmental stress section with in the life cycle described in the step 1, determine the equivalent lifetime t under the normal stress level _Eq, adopt following steps:

A. except the environmental stress section under the normal stress level, the environmental stress section under other stress level need calculate the parameter amount of degradation △ D under other each stress level respectively according to the degeneration physical model of parameter _i, and comprehensively obtain total amount of degradation of other each stress level

K is the stress level number;

B. the function of degeneration physical model is got contraryly, the calculating parameter amount of degradation reaches △ D _tThe time, be equivalent to the loss time t under the normal stress level _Og=f ^-1(△ D _t, S ₀);

C. calculate the equivalent lifetime t of environmental stress section under the normal stress level in the life cycle _Eq=t _Og+ t _No, t wherein _NoBe the action time under the normal stress level.

3. a kind of life of product method for quickly detecting based on physical model according to claim 1, it is characterized in that: described in the step 2 according to life cycle in the environmental stress section that stands of product determine accelerated test stress types and level, adopt following steps:

A. the stress types in the environmental stress section that product stands in the combing life cycle, common stress types has temperature and vibration;

B. according to strenuous test result or the definite stress limit level that keeps the mechanism unanimity of engineering experience, the stress level of choosing in the accelerated test condition is higher than the normal stress level so, but can not be higher than the stress limit level.

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