CN104330353A - New method of indirectly measuring equivalent dynamic stiffness in multipoint-connecting packaging coupling interface - Google Patents

Abstract

The invention discloses a high-precision method of indirectly measuring equivalent dynamic stiffness in a multipoint-connecting packaging coupling interface and belongs to the field of packaging. The high-precision method is mainly characterized in that the equivalent dynamic stiffness in the packaging interface is calculated according to a measured system level frequency-response function and a measured part level frequency-response function. The method includes following steps: (1) arranging a sensor and measuring the frequency-response functions: [HA]<c(a)i(a)>, [HA]<c(a)c(a)>, [HB]<o(b)c(b)> and [HB]<c(b)C(b)>, of a product and a vehicle; (2) performing packaging connection the product and the vehicle, arranging a sensor and measuring the system level frequency-response function [HS]<o(b)i(a)>; and (3) calculating the dynamic stiffness in the packaging coupling interface according to the measured system level frequency-response function and the measured part level frequency-response function. The method is free of shock excitation and vibration picking-up onto the packaging interface and the dynamic stiffness in the packaging interface is measured completely according to the measured frequency-response functions, so that the method is simple in engineering application and is high in precision.

Description

A kind of new method of indirect determination Mulit-point Connection packaging coupled interface equivalence dynamic stiffness

Technical field

The present invention relates to packaging coupled interface parameter recognition technology field, especially relate to the method for testing of packaging coupled interface equivalence dynamic stiffness.

Background technology

To there is damaged phenomenon in product very serious in logistics, and the economic loss caused thus is huge.Protective packaging effectively can reduce the logistics loss of product, and the basis of its design is the dynamic stiffness according to wrapper interface.For packaging coupled interface, normally comprise inner liner, extranal packing box, pallet and other auxiliary stationary installations etc., their performance lump row has become the dynamic stiffness of complicated packaging coupled interface.When dynamic stiffness is larger, the response of packaged product may be amplified and cause product breakage, and when dynamic stiffness is less, the distortion of padded coaming can be very large, thus require that the volume of packing container increases, and causes excessive packaging thus.Therefore, can say, the core of protective packaging design determines suitable packaging coupled interface dynamic stiffness.In the method for testing (comprising time domain approach, frequency domain method etc.) of all multiple solutions dynamic stiffness that mechanical vibration technical field of measurement and test grows up, need high-precision instrument and equipment, need a large amount of measuring points, simultaneously also very high to the requirement of experimental technique itself.Meanwhile, the problem that existing method cannot ensure for the test ubiquity precision comprising the complexity packaging coupled interface dynamic stiffness of multiple unit addressed above, particularly due to the restriction of the physical space of packaging coupled interface own, is difficult to exciting and pick-up.

Summary of the invention

The object of the present invention is to provide a kind of measuring accuracy high, without the need to the method for the easy measurement packaging coupled interface dynamic stiffness of special measurement instrument, engineer applied.

The invention provides the method for testing for packing coupled interface dynamic stiffness, it is characterized in that: the component level frequency response function and the system level frequency response function prediction packaging coupled interface dynamic stiffness that adopt measurement completely, avoid the admittance at Coupling point of measuring system level, comprise the steps:

(1) placement sensor, the respectively frequency response function [H of measurement products (components A) and vehicle (part B) component level _a] _{c (a) i (a)}, [H _a] _{c (a) c (a)}, [H _b] _{o (b) c (b)}, [H _b] _{c (b) c (b)}, wherein [H _x] _ijrepresent and firmly into shape exciting is hammered at j point to parts X, in the acceleration transducer pick-up of i point, the frequency response function obtained;

(2) to product, vehicle, according to actual logistics transportation actual condition, is of coupled connections by packaging, arranges acceleration transducer, direct measuring system horizontal frequency response function [H _s] _{o (b) i (a)}, [H _s] _{o (b) i (a)}represent in the excitation of product point of excitation, simultaneously in the response of vehicle response point acceleration measurement, then gather time-domain signal and the acceleration transducer response signal of excitation, and then obtain the acceleration admittance from point of excitation to response point;

(3) according to the component level frequency response function recorded and system level frequency response function, the dynamic stiffness of packaging coupled interface is directly calculated.Computing formula is as follows:

$\left[K_c\right]=-{\mathrm{\&omega;}}^2{\left(\right[H_A{]}_{c\left(a\right)i\left(a\right)}{\left[H_S\right]}_{o\left(b\right)i\left(a\right)}^{-1}{\left[H_B\right]}_{o\left(b\right)c\left(b\right)}-{\left[H_A\right]}_{c\left(a\right)c\left(a\right)}-{\left[H_B\right]}_{c\left(b\right)c\left(b\right)})}^{-1}.$

Wherein, ω=2 π f, represents sample frequency.

The present invention compared with prior art, has remarkable advantage:

(1) adopt component level frequency response function and the system level frequency response function prediction packaging coupled interface equivalence dynamic stiffness of measurement completely, wherein system level frequency response function has only included [H _s] _{o (b) i (a)}, avoid assembly system coupled interface exciting or pick-up, therefore by the impact of coupled interface physical space restriction, there is the advantages such as engineer applied convenience.

(2) calculate the frequency response function required for formula of dynamic stiffness to be obtained by experiment test completely, avoid FEM (finite element) calculation or theoretical modeling to the dependence of model accuracy.

Accompanying drawing explanation

Fig. 1 Product transport system standard check point schematic diagram.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

Embodiment

The method that the present invention measures packaging coupled interface equivalence dynamic stiffness comprises the following steps:

(1) to product placement sensor, the frequency response function [H of the component level of measurement products _a] _{c (a) i (a}), [H _a] _{c (a) c (a)};

(2) to vehicle placement sensor, the frequency response function [H of the component level of measuring vehicle _b] _{o (b) c (b)}, [H _b] _{c (b) c (b)};

(3) to product, vehicle, according to actual logistics transportation actual condition, is of coupled connections by packaging, arranges acceleration transducer, direct measuring system horizontal frequency response function [H _s] _{o (b) i (a)};

(4) apply following formula to calculate packaging coupled interface dynamic stiffness

$\left[K_c\right]=-{\mathrm{\&omega;}}^2{\left(\right[H_A{]}_{c\left(a\right)i\left(a\right)}{\left[H_S\right]}_{o\left(b\right)i\left(a\right)}^{-1}{\left[H_B\right]}_{o\left(b\right)c\left(b\right)}-{\left[H_A\right]}_{c\left(a\right)c\left(a\right)}-{\left[H_B\right]}_{c\left(b\right)c\left(b\right)})}^{-1}.$

Above-mentioned (1), (2), (3) measurement of step medium frequency response function can be obtained by simple ripe " exciting test ", complete by " power hammer-accelerometer-multi-channel signal acquiring analytic system " hardware testing system, this system is public physical construction kinetic test analytic system, mainly comprise the power hammer of exciting, one group of sensor-accelerometer of vibratory response test, and multi-channel signal acquiring analytic system, as domestic DASP intelligent signal energy acquisition processing system, 16 or 32 passages, external as LMS, the systems such as BK, multi-channel signal acquiring analyser is primarily of advance signal regulator, (time-frequency Dynamic Signal reads for analog to digital converter and software kit, analyze, display, export, the functions etc. such as printing).

Above-described embodiment is the embodiment that the present invention recommends; but embodiments of the present invention are not restricted to the described embodiments; the amendment made under other any does not deviate from core essence of the present invention and principle, substitute, combination, simplify the substitute mode that all should be equivalence, be included within protection scope of the present invention.

Claims (4)

1. a new method for indirect determination Mulit-point Connection packaging coupled interface equivalence dynamic stiffness, is characterized in that, comprise the steps:

(1) placement sensor, the respectively frequency response function [H of measurement products (components A) and vehicle (part B) component level _a] _{c (a) i (a)}, [H _a] _{c (a) c (a)}, [H _b] _{o (b) c (b)}, [H _b] _{c (b) c (b)}, wherein [H _x] _ijrepresent and firmly into shape exciting is hammered at j point to parts X, in the acceleration transducer pick-up of i point, the frequency response function obtained;

(2) to product, vehicle, according to actual logistics transportation actual condition, is of coupled connections by packaging, arranges acceleration transducer, direct measuring system horizontal frequency response function [H _s] _{o (b) i (a)}, [H _s] _{o (b) i (a)}represent in the excitation of product point of excitation, simultaneously in the response of vehicle response point acceleration measurement, then gather time-domain signal and the acceleration transducer response signal of excitation, and then obtain the acceleration admittance from point of excitation to response point;

(3) packaging coupled interface equivalence dynamic stiffness [K is directly calculated according to the system level frequency response function measured and component level frequency response function _c].

2. the new method of a kind of indirect determination Mulit-point Connection packaging coupled interface equivalence dynamic stiffness according to claim 1, it is characterized in that, the system level frequency response function of described measurement only includes [H _s] _{o (b) i (a)}.

3. the new method of a kind of indirect determination Mulit-point Connection packaging coupled interface equivalence dynamic stiffness according to claim 2, it is characterized in that, the frequency response function of required measurement directly adopts the acceleration admittance of measurement to express.

4. the new method of a kind of indirect determination Mulit-point Connection packaging coupled interface equivalence dynamic stiffness according to claim 3, it is characterized in that, the computing formula of dynamic stiffness is

$\left[K_c\right]=-{\mathrm{\&omega;}}^2{\left(\right[H_A{]}_{c\left(a\right)i\left(a\right)}{\left[H_S\right]}_{o\left(b\right)i\left(a\right)}^{-1}{\left[H_B\right]}_{o\left(b\right)c\left(b\right)}-{\left[H_A\right]}_{c\left(a\right)c\left(a\right)}-{\left[H_B\right]}_{c\left(b\right)c\left(b\right)})}^{-1}.$