System level drop-impact simulation and validation of handheld radio devices.
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
This project was concerned with the development of a finite element model capable of simulating a drop-impact event of handheld radio devices. Handheld radios call for exceptional robustness and reliability due to their deployment in critical applications. The development of a drop-impact finite element model aims to provide greater understanding of impact behaviours, this insight would ultimately be used to develop more robust and optimised handheld electronic products. Before such analysis tools can be introduced into the product development cycle an understanding of finite element methods, of setup parameters for the finite element solver and the accuracy of simulation results must be considered. Experimental results were used throughout the project to validate the finite element models developed. A drop-impact test rig was designed and constructed to control both impact orientation and velocity of the handheld radios tested. Drop-impact modelling of a handheld radio is extremely challenging because of the complex interaction of the contacting surfaces, the complex stress-strain and damping characteristics of the materials, and the excitation of the high frequency modes. For this reason, the finite element model was developed in two stages: a simplified radio was used to develop the understanding of the above complexities and then the understanding implemented in a more detailed radio model. The mesh size of the finite elements, the elastic and the damping characteristics of the materials and the contact conditions for the simplified radio model were varied to understand their influence on the simulation results. The finite element input settings and parameters were altered to give better agreement with the experimental results of the simplified radio model. The detailed radio was subsequently modelled. The lessons learnt from the simplified radio model were applied to the analysis of the detailed radio assembly. Despite general agreements, there were some differences between the finite element and experimental results which was attributed to the high complexity of the model. The project delivered a workable finite element model capable of analysing the drop-impact event of handheld radio devices. Suggestions have been provided that would further improve the quality of the model.