UBC Theses and Dissertations
A numerical investigation of ballistic impact on textile structures Noori, Ali Shahkarami
The present work focuses on numerical investigation of impact on textile materials. An analytical model is proposed based on the theory of single yarn impact, to evaluate the energy absorbed by a fabric panel. This model is capable of evaluating the total absorbed energy and its components knowing the displacement time-history of the projectile. A numerical model is used to simulate the behaviour of a fabric panel under impact. This model approximates the fabric as an assembly of nodal masses attached to each other by means of string elements in the principal directions. A computer code is developed that is capable of modelling the impact of a blunt cylindrical projectile on rectangular fabric panels with various types of boundary conditions. The code predicts the time-histories of the nodal displacements, as well as forces in the string elements. Based on these, energy stored in the system in the form of strain energy in the strings and kinetic energy of inplane and transverse motion of the masses can also be evaluated. The numerical predictions are successfully compared with instrumented impact test results. Finally, a series of numerical experiments are performed to investigate the sensitivity of the response to different input parameters. The response is found to depend on many geometric and material parameters, emphasizing the importance of having an accurate knowledge of some of the input parameters. In particular, boundary conditions are found to affect the response significantly. It is also observed that increasing the elastic modulus or breaking strain of the yarns affects the energy absorption of the target favourably. Increasing the initial crimp strain is found to decrease the impact energy absorption, similar to increasing the gap between the layers of a multi-layer fabric.
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