Finite Element Verification Of Accelerated Random Vibration Theory Based On G_rms-N

At present,accelerated vibration testing in the field of transportation and packaging is an effective research method for analyzing and measuring product fatigue damage.The current existing fatigue model for accelerated vibration testing of transportation packaging is a power function model.Due to the complexity of packaging products,this model cannot contain all forms of fatigue damage to materials and components.At the same time,in the process of analyzing fatigue damage,the von Mises equivalent stress is usually used as the standard for evaluating the fatigue damage of the product.This requires the analysis or measurement of the local stress field of the product during the random vibration process.It’s very difficult.Through theoretical derivation,the research team linked the stress power spectrum of the dangerous points inside the product parts with the power spectrum of the component acceleration,developed the theoretical method of acceleration vibration test suitable for actual measurement,and formed the corresponding logistics transportation packaging evaluation system.Because this method is derived from the von Mises equivalent stress as a measurement standard,it is necessary to compare and verify from the two evaluation criteria of the equivalent stress RMS（Root Mean Square）value at the dangerous point and the acceleration RMS value of the component to prove the correctness of the product accelerated random vibration test method based on the acceleration RMS value proposed by the research group.At present,random vibration analysis of transportation packaging is generally suitable for stationary Gaussian random excitation signals,but in actual transportation,random vibration excitation signals often show non-Gaussian characteristics.Therefore,research on fatigue damage of products under non-Gaussian random vibration and then research based on non-Gaussian excitation Accelerated random vibration of the lower transportation packaging is of great significance to reproduce the product response under the real excitation signal.In response to the above issues,the specific research content and conclusions of this article are as follows:（1）The theory proposed by the research group is further deduced,and the general formula of the time compression ratio of the accelerated random vibration test under multi-axis excitation of the product is obtained.In this paper,based on the method of finite element analysis,multi-axis random vibration analysis,and the von Mises equivalent stress power spectrum at different points of danger of the product is obtained,respectively.Calculate the acceleration time compression ratio of the product under different excitation levels from the perspective of the response power spectrum of the dangerous point inside the product component and the acceleration power of the component.Finally,compare the time compression ratios obtained under these two standards to verify the consistency.The correctness of the theoretical method of the random vibration test based on the root mean square value of acceleration proposed by the laboratory is presented.（2）According to the acceleration random vibration analysis of the real product of a certain brand of car circuit board,the excitation power spectrum of the three-axis direction is different.The angles of root mean square and root mean square in response to the equivalent stress respectively calculate the acceleration random vibration time compression ratio,which verifies the universality of the theoretical method proposed by the research group.（3）For the packaging products proposed by the research group,the theoretical method of accelerated random vibration test based on the acceleration RMS value of the excitation was further studied.The calculation formula of time compression ratio of non-Gaussian accelerated random vibration under specified steepness is derived.The product model was subjected to three excitation kurtosis values and five excitation levels using finite element analysis.Random vibration analysis.The results show that the time compression ratio calculated by the proposed laboratory random acceleration vibration theoretical method based on the acceleration RMS value of component excitation and the time compression ratio calculated by the equivalent stress RMS value at the dangerous point response The coincidence proves that the method is also consistent and applicable under non-Gaussian excitation.In this paper,the finite element method is used to simulate the accelerated random vibration test of the product in the laboratory.Through theoretical derivation and finite element analysis,the theoretical method of the accelerated random vibration test based onG_rms-Nproposed by the research group is directly verified.At the same time,the theory was further deduced,and the theoretical method of the product non-Gaussian accelerated random vibration test were obtained through finite element analysis.