دانلود رایگان مقاله انگلیسی مدل سازی برای ساختارهای CFRP تحت خرد شدگی شبه استاتیک - الزویر 2018

Abstract

Carbon fiber reinforced plastic (CFRP) composite materials demonstrate significant promise to further improve weight to performance in automotive engineering. Nevertheless, design of CFRP components for crashworthiness criteria remains rather challenging and typically requires laborious trial-and-error processes. This study aims to promote computational design of CFRP structures by establishing effective constitutive model that is implemented in the commercial finite element code Abaqus/Explicit. Two different numerical models (namely, the single layer shell model and the stacked shell model) were developed to simulate experimental crushing tests on the square CFRP tube. The effects of key parameters for these two FE models were analyzed, respectively. The comparisons of numerical results with experimental data indicated that the 9 layers stacked shell model is capable of reproducing experimental results with relatively high accuracy. Based on the validated modeling approach, crushing behaviors of several CFRP thin-walled structures with different cross sectional geometries and thicknesses were further explored. The failure modes and key indicators in relation to the structural crashworthiness were investigated for identifying a best possible sectional configuration. It is found that the circular tube shows superior specific energy absorption capacity of all different tubal configurations with the same wall thickness, meaning that the tube with circular section is of good potential as a crashworthy CFRP structure.

6. Conclusions

This study developed two different numerical models (namely single layer shell model and stacked shell model) based on a proposed constitutive model to simulate experimental crush tests on a square CFRP tube. The influence of key modeling parameters for these two FE models were analyzed; and their overall suitability was assessed to provide an effective and accurate prediction. Further, the crushing behaviors of several CFRP tubes with different cross sectional shapes and wall thickness have been investigated through numerical simulations to explore the most suitable sectional configurations for crashworthiness design. Within the limitations, the following conclusion can be drawn from this study:

(1) The simulation based on the single shell layer model is unable to realistically capture the failure mechanism and energy absorption capacity obtained from the experimental tests, specifically underestimating the crushing loads and EA considerably.

(2) The 9 layer stacked model with µ = 0.2 is able to predict the damage progression, failure modes and the crashworthiness indicators of the CFRP square tube most accurately in comparison of the experimental results.

(3) Raising the friction coefficient increases the EA for both the FE models.

(4) In the stacked shell model, reducing the number of layers may change the main collapse mode, and consequently vary the value of EA.

(5) For the tubes with different sectional profiles but the same wall thickness and perimeter (this the same weight), the SEA increases with raising the number of edges. The effect of thickness on SEA of tubes with pentagon, hexagon and circle profiles is relatively small in comparison with the triangle and square profiles. The circular tube exhibits superior energy absorption capacity of all these tubes concerned, thereby being of great potential to be a crashworthy structure.