CN102411650B - Generation method of complex impact acceleration approximate pulse curve of automobile - Google Patents

Abstract

The invention discloses a generation method of a complex vehicle impact acceleration approximate pulse curve, which comprises the following steps of: carrying out the time-domain analysis of actual impact pulses of the vehicle impact to obtain the characteristics of the pulses in time domain; carrying out the frequency domain analysis of the actual impact pulses of the vehicle impact to obtain the characteristics of the pulses in the time domain; establishing a pulse characteristic equation; and according to the pulse characteristic equation, selecting characteristic parameters to obtain an approximate pulse curve characteristic equation and thus obtain an approximate pulse curve of the vehicle impact. The generation method of the complex vehicle impact acceleration approximate pulse curve is adopted, so the complex impact acceleration curve is generated by establishing a mathematical model and the parameters of the impact acceleration in the time domain and frequency domain are analyzed from the angle of energy. The generation method has the advantages of simpleness in operation, rapidness and high accuracy.

Description

Automobile collision complex impact acceleration approximate pulse curve production method

Technical field

The present invention relates to a kind of approximate pulse curve production method, espespecially a kind of automobile collision complex impact acceleration approximate pulse curve production method.

Background technology

The security of automobile is most important performance index, and the method for the impact test of automobile is absolutely necessary in the design of automobile, manufacture process.In vehicle passive safety research, usually adopt real vehicle collision test and the emulation of computing machine impact simulation to carry out the crash-worthiness evaluation.The process of car crass is two objects interacted and be accompanied by sizable energy within the extremely short time exchange, and impact acceleration is the key factor that affects collision energy and result.The accelerating curve of car crass be necessity of studying in advance, can access deformation in all parts, speed and accekeration, and the distribution of ess-strain by the accelerating curve of car crass.Thereby but reference standard judges whether to satisfy the requirement of automobile relevant laws and regulations and carries out the improvement of structure.

The vehicle frame impulse test is a kind of new test method, is applicable to the collision safety architecture advances test of vehicle body frames structure automobile.Vehicle frame impulse test Acceleration pulse is similar to real vehicle collision test, could quick and precisely directly test and estimate the collision actual effect.Waveform generator is critical component in the vehicle frame impact test apparatus, and the generation of automobile impact curve is the core of waveform generator with reproduction.

It is very complicated that actual acceleration impacts curve, when carrying out physics or l-G simulation test, often can't obtain the test pulse very high with the actual pulse degree of approximation, brings very large uncertainty and error to test, can't accurately check the collision resistance to vibration of automobile.

Patent No. CN 101608970 has proposed a kind of reproducing apparatus of automobile impact curve.Device comprises waveform generator, barrier walls, collision chassis.Can produce different extruding forces with difform energy absorbing tube, thereby simulate different automobile impact curves.

Patent No. CN 101603879 has proposed a kind of method and device of simulating automobile collision complex curve.Device comprises barrier walls, chassis and energy absorbing component.Utilize metal tube being subject to the do time spent of diameter greater than the collision bar of its internal diameter, can be expanded by collision bar, produce dilatational strain, by the expansion absorption energy, chassis is slowed down, produce needed squiggle.

As seen present, waveform generator all adopts gas, liquid or mechanical hook-up simulation to produce automobile impact curve, but the impulse test Acceleration pulse of complexity is difficult to produce and control, and the relation between complicated impact acceleration curve and the impact energy is also beyond expression of words.

Summary of the invention

The object of the invention is to overcome the defective of prior art, and provide a kind of automobile collision complex impact acceleration approximate pulse curve production method, it has advantage simple to operate, quick, that degree of accuracy is high, realized producing complicated impact acceleration curve by setting up mathematical model the parameter from the angle analysis impact acceleration time-domain and frequency-domain of energy.

The technical scheme that realizes above-mentioned purpose is:

Automobile collision complex impact acceleration approximate pulse curve production method of the present invention comprises the steps:

S1: time-domain analysis is carried out in the real impact pulse to car crass, obtains the feature of described pulse on time domain;

S2: frequency-domain analysis is carried out in the real impact pulse to car crass, obtains the feature of described pulse on frequency domain;

S3: set up the pulse characteristics equation;

S4: according to described pulse characteristics equation, select characteristic parameter, obtain approximate pulse curve secular equation, and then obtain the approximate pulse curve of car crass.

Above-mentioned pulse characteristics equation comprises the general waveform character equation of broad sense half-sine pulse and its secular equation of general waveform of superpositing vibration half-sine pulse;

The general waveform character equation of described broad sense half-sine pulse is:

$G_{\mathrm{es}}(t,\mathrm{\ξ})=x_n*\frac{\sin (\mathrm{\π}*t/\mathrm{\τ})}{\sin (\mathrm{\π}*\mathrm{\ξ})}*\exp (\mathrm{\π}*\frac{\mathrm{\ξ}-(t/\mathrm{\τ})}{\mathrm{tg}(\mathrm{\π}*\mathrm{\ξ})});$

X wherein _nFor peak value of pulse, ξ are that pulse front edge broadband, τ are the pulse broadband on the zero line, t is the time, and the pulse front edge broadband refers to that pulse rises to the ratio of pulse width on time of peak value of pulse and the zero line;

Its secular equation of general waveform of described superpositing vibration half-sine pulse is:

G _esk(t,k,k _h,n)=x _n*k _h*(sin(π*t/τ)+k*sin(2*π*n*t/τ))；

X wherein _nFor peak value of pulse, ξ are that pulse front edge broadband, τ are pulse broadband, the k on the zero line _hBe dimensionless factor, 0＜k _h＜1, k is that size, the n of the relative basic waveform peak value of superpositing vibration is the periodicity of superpositing vibration.

Said method is in also further comprising by relative root-mean-square criterion λ _ФThe step that the approximation quality of the approximate pulse curve of described acquisition is assessed:

Above-mentioned relative root-mean-square criterion λ _ФEquation be:

${\mathrm{\λ}}_{\mathrm{\φ}}=\sqrt{\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\left(\frac{x_{a,i}-x_{n,i}}{x_{n,\max }}\right)}^2}{n(n-1)}};$

Wherein: x _{A, i}Be the ordinate value of the approximate waveform of the same independent variable of correspondence, x _{N, i}Ordinate value for the real pulse shape of the same independent variable of correspondence; x _{N, max}Be the peak value of real pulse shape, n is that the ordinate of getting in the calculating is counted.

The present invention has been owing to adopted above technical scheme, makes it have following beneficial effect to be:

Realized producing complicated impact acceleration curve by setting up mathematical model, realized the parameter from the angle analysis impact acceleration time-domain and frequency-domain of energy, can contrast the buckles size of collision, be convenient to simulation analysis, also can estimate process and the feature of the impact of collision.Generation and control for automobile impact curve bring great convenience, and also provide favourable means for the emulation of computing machine impact simulation.Solved the key issue that produces automobile impact curve in impact test and the impact simulation emulation, for producing automobile impact curve and control, the gas of impact test, liquid or mechanical hook-up simulation provide simple and easy, utility easily and efficiently, solved problem beyond expression of words between complicated impact acceleration curve and the impact energy, this method has wide utilization prospect, and its economic benefit and social benefit are very considerable.

Description of drawings

Fig. 1 is the process flow diagram of automobile collision complex impact acceleration approximate pulse curve production method of the present invention.

Embodiment

The invention will be further described below in conjunction with the drawings and specific embodiments.

At first choose some real impact pulse curves.

See also Fig. 1, automobile collision complex impact acceleration approximate pulse curve production method of the present invention comprises the steps:

S1: time-domain analysis is carried out in the real impact pulse to car crass, obtains the feature of pulse on time domain;

Research method (signal analysis method) according to the impact acceleration waveform, seek the waveform character parameter of shock pulse, by the analysis of actual pulse as can be known, actual pulse is divided into two class impulse forms, the i.e. half-sine pulse of broad sense half-sine pulse and superpositing vibration usually.

S2: frequency-domain analysis is carried out in the real impact pulse to car crass, obtains the feature of pulse on frequency domain;

Can know the principal character of pulse on time domain by time-domain analysis, by the frequency-domain analysis of pulse, then can find out the feature of pulse on frequency domain, i.e. the distribution situation of pulse on each frequency band.After each actual input stroke is carried out Fourier transform, can obtain the frequency domain characteristic of real impact pulse.Spectrogram according to the real impact pulse, the frequecy characteristic that can find out the real impact pulse mainly concentrates in certain frequency band, especially the amplitude in low frequency is more obvious, when carrying out Pulse Design, the main frequency section of pulse can be made as low frequency.In addition, can also from spectrogram, draw the concrete amplitude of actual pulse in each frequency band, by with the spectrum analysis of actual pulse, can find equally the spectrum curve of pulse and the relation that coordinate axis surrounds area, namely numerical value is the pulse shock energy.

S3: set up the pulse characteristics equation;

According to the waveform superposition principle as can be known, any complicated wave form can be formed by N simple wave form (cycle, aperiodic or at random) stack.Two different frequencies and the waveform in cycle are superimposed as complicated wave form.By the time-domain analysis of pulse as can be known, actual pulse can be made of broad sense sine pulse or superpositing vibration half-sine pulse.Namely set up the pulse characteristics equation, can produce complex impact acceleration approximate pulse curve according to the needs of impact energy, reproduce size and the real impact accelerating curve of impact energy, be procedural theory research and the emulation of car crass, the Acceleration pulse of vehicle impact testing produces with control instrument is provided.

The pulse characteristics equation comprises the general waveform character equation of broad sense half-sine pulse and its secular equation of general waveform of superpositing vibration half-sine pulse;

The general waveform character equation of broad sense half-sine pulse is:

$G_{\mathrm{es}}(t,\mathrm{\ξ})=x_n*\frac{\sin (\mathrm{\π}*t/\mathrm{\τ})}{\sin (\mathrm{\π}*\mathrm{\ξ})}*\exp (\mathrm{\π}*\frac{\mathrm{\ξ}-(t/\mathrm{\τ})}{\mathrm{tg}(\mathrm{\π}*\mathrm{\ξ})});$

X wherein _nFor peak value of pulse, ξ are that pulse front edge broadband, τ are the pulse broadband on the zero line, t is the time, and the pulse front edge broadband refers to that pulse rises to the ratio of pulse width on time of peak value of pulse and the zero line, and its span is: 0＜ξ＜1;

Its secular equation of general waveform of superpositing vibration half-sine pulse is:

G _esk(t,k,k _h,n)=x _n*k _h*(sin(π*t/τ)+k*sin(2*π*n*t/τ))；

X wherein _nFor peak value of pulse, ξ are that pulse front edge broadband, τ are pulse broadband, the k on the zero line _hBe dimensionless factor, 0＜k _h＜1, k is that size, the n of the relative basic waveform peak value of superpositing vibration is the periodicity of superpositing vibration.

S4: according to the pulse characteristics equation, select characteristic parameter, obtain approximate pulse curve secular equation, and then obtain the approximate pulse curve of car crass.

Said method is in also further comprising by relative root-mean-square criterion λ _ФThe step that the approximation quality of the approximate pulse curve that obtains is assessed:

Above-mentioned relative root-mean-square criterion λ _ФEquation be:

${\mathrm{\λ}}_{\mathrm{\φ}}=\sqrt{\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\left(\frac{x_{a,i}-x_{n,i}}{x_{n,\max }}\right)}^2}{n(n-1)}};$

Wherein: x _{A, i}Be the ordinate value of the approximate waveform of the same independent variable of correspondence, x _{N, i}Ordinate value for the real pulse shape of the same independent variable of correspondence; x _{N, max}Be the peak value of real pulse shape, n is that the ordinate of getting in the calculating is counted.

Time domain waveform according to the actual pulse curve, selection is by the general waveform character equation of broad sense half-sine pulse or the secular equation of superpositing vibration half-sine pulse, each characteristic parameter of choose reasonable, the complicated impact acceleration curve approximate with real pulse shape be can generate, Physical Experiment and analog simulation conveniently carried out.The complicated impact acceleration curve that generates is in full accord with the spectrum signature of actual pulse in the main frequency scope, be that main frequency energy section is identical, prove that the complicated impact acceleration curve of secular equation generation is at the alternative actual pulse curve of energy point of view.

Below embodiment has been described in detail the present invention by reference to the accompanying drawings, and those skilled in the art can make the many variations example to the present invention according to the above description.Thereby some details among the embodiment should not consist of limitation of the invention, and the scope that the present invention will define with appended claims is as protection scope of the present invention.

Claims (2)

1. an automobile collision complex impact acceleration approximate pulse curve production method is characterized in that, comprises the steps:

S1: time-domain analysis is carried out in the real impact pulse to car crass, obtains the feature of described pulse on time domain;

S2: frequency-domain analysis is carried out in the real impact pulse to car crass, obtains the feature of described pulse on frequency domain;

S3: according to described pulse in the feature on the time domain and described pulse the feature on frequency domain set up the pulse characteristics equation, described pulse characteristics equation comprises the general waveform character equation of broad sense half-sine pulse and the general waveform character equation of superpositing vibration half-sine pulse;

The general waveform character equation of described broad sense half-sine pulse is:

X wherein _nFor peak value of pulse, ξ are that pulse front edge broadband, τ are the pulse broadband on the zero line, t is the time, and the pulse front edge broadband refers to that pulse rises to the ratio of pulse width on time of peak value of pulse and the zero line;

Its secular equation of general waveform of described superpositing vibration half-sine pulse is:

G _esk(t,k,k _h,n)=x _n*k _h*(sin(π*t/τ)+k*sin(2*π*n*t/τ))；

X wherein _nFor peak value of pulse, τ are that pulse broadband, t on the zero line is the time, k _hBe dimensionless factor, 0＜k _h＜1, k is that size, the n of the relative basic waveform peak value of superpositing vibration is the periodicity of superpositing vibration;

S4: according to described pulse characteristics equation, select characteristic parameter, obtain approximate pulse curve secular equation, and then obtain the approximate pulse curve of car crass.

2. automobile collision complex impact acceleration approximate pulse curve production method as claimed in claim 1 is characterized in that also further comprising by relative root-mean-square criterion λ _ΦThe step that the approximation quality of the approximate pulse curve of described acquisition is assessed:

Described relative root-mean-square criterion λ _ΦEquation be:

Wherein: x _{A, i}Be the ordinate value of the approximate waveform of the same independent variable of correspondence, x _{N, i}Ordinate value for the real pulse shape of the same independent variable of correspondence; x _{N, max}Be the peak value of real pulse shape, n is that the ordinate of getting in the calculating is counted.

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