Optimization of the semi-hexagonal geometry of a composite crush structure by finite element analysis

In the present paper a numerical model for predicting the crushing behaviour of semi-hexagonal E-glass/polyester composite structures has been developed. Qualitative and quantitative analysis have shown that the results of the simulation are accurately predicted comparing with the experimental data. The peak force has been predicted with 7.5% of error while the mean force of the crushing process, the total amount of absorbed energy and the specific energy absorption capability have been simulated within 1% of error. Moreover the effect of the wall angle of the semi-hexagonal section and the effect of the overall size of the semi-hexagonal section have been numerically analyzed. The crushing process becomes stable when the wall angle is higher than 50° and the highest specific energy absorption values are obtained using the wall angle of 60° and wall length of 10 mm. Higher wall angles and wall lengths increases the stress concentration in the edges of the semi-hexagonal section and in consequence, the load carrying capability of the structure decreases dissipating less energy.