CN104318044A - Determination method of outwork fault tolerance of canopy organic glass - Google Patents

Abstract

The invention belongs to the field of fatigue, and relates to a determination method of the outwork fault tolerance of canopy organic glass. The formulation method is characterized by comprising the following steps: determining a typical fault mode of the canopy organic glass; prefabricating a tensile fatigue standard sample of the canopy organic glass, a fault glass element test piece and a fault-repaired organic glass test piece; carrying out a defect and no-defect canopy glass aging test; carrying out fatigue performance test by applying an aged test piece; compiling a canopy fatigue load spectrum; establishing a canopy fatigue detail analysis model; calculating a canopy organic glass stress spectrum under the fatigue load spectrum; adopting element fatigue performance test data to estimate the service life of the canopy organic glass; and according to an estimation result, giving the fault tolerance of the canopy glass under the target service life. The invention can drastically improve the use efficiency of a canopy, reduce maintenance cost, guarantee use safety and exhibits important meanings and obvious economic benefit.

Description

The fault-tolerant formulating method of a kind of canopy organic glass line

Technical field

The invention belongs to aircraft fatigue field, relate to the fault-tolerant formulating method of a kind of canopy organic glass line.

Background technology

Canopy organic glass is in the use procedure of outfield, due to the load effect, the dust storm that are subject to blow, maintenance process neglects and collides with and inevitably there will be various damage, and the damage in the past occurred for canopy organic glass surface adopted two kinds of processing modes usually: break down with regard to grinding process or provide the suggestion whether processed by rule of thumb.First kind of way can ensure the use safety of canopy, but wastes a large amount of manpower and materials, limits the use of canopy; The repairing standard that the second way provides may too be guarded or too danger, can not guarantee the use safety of canopy.Advantage of the present invention is: application test and the fault-tolerance analyzing the method determination canopy organic glass combined, the service efficiency of canopy can be improved significantly, reduce maintenance cost, and can use safety be ensured, significant, remarkable in economical benefits.

Summary of the invention

The object of the invention is: the formulating method proposing a kind of canopy organic glass operational failure tolerance limit, simply, exactly can carry out analysis of fatigue, provide the operational failure standard of canopy organic glass, workflow is shown in Fig. 1.

Technical scheme of the present invention is: a kind of formulating method of canopy organic glass operational failure tolerance limit, is characterized in that, comprise the steps:

The first, perspex test part after prefabricated organic glass stretching fatigue criteria sample, the perspex test part being with scuffing and crazing fault and fault restoration;

The second, carry out organic glass aging test;

3rd, apply aging after perspex test part carry out fatigue property test;

4th, establishment canopy fatigue load spectrum;

5th, set up the tired details finite element analysis model of canopy;

6th, canopy organic glass stress spectra under calculating fatigue load spectrum;

7th, adopt testpieces fatigue property test data to estimate the canopy organic glass life-span;

Estimation adopts 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 _ifor the cycle index of 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:

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

In formula: f is dispersion coefficient;

T _mbfor canopy target life objective.

Adopt respectively and with the canopy glass elements fatigue behaviour data after defect, band defect and defect repair, life estimate is not carried out to canopy organic glass, obtain the estimated life of different depth defect canopy organic glass.

9th, provide the fault-tolerance of canopy glass under target life objective according to estimation result

According to the life-span result of calculation of various lesion depths canopy organic glass compared with index of aging, as T < T _mb, then under this depth of defect, estimated life can not meet the requirement of index of aging, need place under repair to defect, determines the fault-tolerance of canopy organic glass thus.

Advantage of the present invention is: the canopy organic glass of method to tape jam that application test combines with analysis carries out life appraisal, and process is fairly simple, and the method meets conventional strength and checks theory, is beneficial to intensity slip-stick artist and understands and grasp.Amount of calculation is also relatively less, can provide the canopy operational failure tolerance limit facilitating outfield to operate accurately, save maintenance cost, significant, remarkable in economical benefits.

Accompanying drawing explanation

Fig. 1 is that canopy organic glass fault-tolerance formulates process flow diagram

Fig. 2 is organic glass tensile fatigue typical element figure

Fig. 3 is that band scratches organic glass tensile fatigue typical element figure

Embodiment

Below by specific embodiment, also the present invention is described in further detail by reference to the accompanying drawings.

Shown below is the example that certain canopy organic glass operational failure tolerance limit is formulated.

First, the typical fault mode of canopy organic glass is determined

Through investigation and analysis, determine the representative failure mode that in use procedure, canopy glass occurred: crazing and scuffing, and the depth range that defect may occur.

The first, perspex test part after prefabricated canopy organic glass tensile fatigue standard sample, fault glass elements testpieces and fault restoration

The job operation of testpieces is as follows:

1) first prefabricated canopy glass stretching fatigue criteria sample, is shown in Fig. 2;

2) typical Scratch Test part is the width adopting icking tool constant depth and cut on the basis of tensile fatigue standard sample, and mark the cut of different angles along testpieces axis direction, Fig. 3 is shown in by typical sample;

3) typical crazing sample is placed on Apparatus for Bending at low-temp by tensile fatigue standard sample, in active section brushing acetone and other organic solvent, and prefabricated crazing after loading;

4) after repairing sample be prefabricated typical case scratch and crazing sample basis on adopt the mode of grinding and polishing to eliminate defect, different according to the degree of depth of defect, precast sample after the reparation of different-thickness.

The second, carry out canopy glass aging test

According to the requirement in canopy serviceable life, carry out aging test to canopy glass test part, digestion time is consistent with canopy target lifetime.

3rd, apply aging after testpieces carry out fatigue property test

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

Different depth scratches organic glass normal temperature tensile fatigue conditional fatigue limit in table 1.

Table 1 different depth scratches organic glass normal temperature tensile fatigue conditional fatigue limit

From table 1, during scratch depth 0.4mm, organic glass fatigue behaviour is decreased significantly.

4th, establishment canopy fatigue load spectrum

According to loading spectrum Planning procedure establishment canopy fatigue load spectrum, be divided into 16 load working conditions, contain canopy high temperature, low temperature, middle temperature and the various spectral pattern of normal temperature within the scope of whole envelope.

5th, set up the tired detail analysis model of canopy

Built by canopy organic glass as volume elements, through-thickness is divided into 10 layers, and the thermograde of calculating is applied on canopy organic glass.By the inside surface of the supercharging load applying in passenger cabin to organic glass, aerodynamic loading is applied to the outside surface of organic glass, and the connection between simulation skeleton and mouth frame that imposes restriction on two side skeletons.

6th, canopy organic glass stress spectra under calculating fatigue load spectrum

Adopt the tired detail analysis model of canopy to carry out stress analysis to the different sections in temperature loading spectrum, obtain corresponding stress spectra in table 2.

Table 2 canopy stress spectra

7th, adopt component fatigue performance test data to estimate the canopy organic glass life-span

The S-N Curve of design feature to test according to canopy is revised, and correction factor is in table 3.

Table 3 organic glass S-N curve amendment coefficient

Adopt revised S-N curve to be that canopy organic glass under 1200 pilot time loading spectrums carries out life estimate to the corresponding life-span, it is 6 that life estimate chooses dispersion coefficient, and different depth scratches the accumulated damage of organic glass in table 4:

Table 4 different depth scratches the accumulated damage of organic glass

Life-span without the canopy organic glass scratched is pilot time;

The life-span of the canopy organic glass of scratch depth 0.3mm is pilot time;

The life-span of the canopy organic glass of scratch depth 0.4mm is pilot time.

8th, provide the fault-tolerance of canopy glass under target life objective according to estimation result

Can meet the requirement at target life objective 1200 pilot time according to the scuffing that is below 0.3mm of estimation result scratch depth, scratch depth 0.4mm then fatigue behaviour declines comparatively large, can not meet the demand of target life objective.

Claims (1)

1. a formulating method for canopy organic glass operational failure tolerance limit, the typical fault mode of canopy organic glass, for scratching and crazing, is characterized in that, comprises the steps:

The first, perspex test part after prefabricated organic glass stretching fatigue criteria sample, the perspex test part being with scuffing and crazing fault and fault restoration;

The second, carry out organic glass aging test;

3rd, apply aging after perspex test part carry out fatigue property test;

4th, establishment canopy fatigue load spectrum;

5th, set up the tired details finite element analysis model of canopy;

6th, canopy organic glass stress spectra under calculating fatigue load spectrum;

7th, adopt testpieces fatigue property test data to estimate the canopy organic glass life-span;

Estimation adopts 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 _ifor the cycle index of 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:

$T=\frac{T_{\mathrm{mb}}}{f\&CenterDot;\mathrm{\&Sigma;}{D}_i}---\left(2\right)$

In formula: f is dispersion coefficient;

T _mbfor canopy target life objective;

Adopt respectively and with the canopy glass elements fatigue behaviour data after defect, band defect and defect repair, life estimate is not carried out to canopy organic glass, obtain the estimated life of different depth defect canopy organic glass;

8th, provide the fault-tolerance of canopy glass under target life objective according to estimation result

According to the life-span result of calculation of various lesion depths canopy organic glass compared with index of aging, as T < T _mb, then under this depth of defect, estimated life can not meet the requirement of index of aging, need place under repair to defect, determines the fault-tolerance of canopy organic glass thus.