Drop Impact Dynamics And Crashworthiness Robust Design For Manufactured Products

Drop-impact lead to failure for various types of small electronic motors in useful life period. At present, design cycles for manufactured produce is preliminary design, sample impact experiments and re-design. The final product has to use standard experiments to check the drop-impact on prototype product to achieve the tough crashworthiness. However, the product still will suffer drop impact failure, even though the sample drop impact passed. During manufacture processing, the drop-impact is a major product failure reason. Furthermore, the traditions design model is time-consuming and highly-cost so that it is not well-suitable for small type manufactured produce. Shortening the design cycle of drop impact and providing crashworthiness robust design for manufactured produce are urgently needed.The main work of this thesis can be summarized as follows:Considering particularity and uncertainty of drop impact crashworthiness design, literature review from the research about the dynamic response of drop impact and impact crashworthiness robust design has been done. Drop impact crashworthiness robust design optimize frame is presented and developed based on crashworthiness evaluation for virtual drop test. This work enrichs design theory and method for dynamic design. In this thesis, precision electronic products mobile hard disk and liquid-sold coupled fluid-filled container are chosen as two samples to investigate the capability of dynamic drop-impact, crashworthiness design, optimism structural parameters, and crashworthiness robust design.A 2.5 inch mobile hard disk finite element modal is modeled according to key components function of head actuator arm assembly. Parameters of modal are achieved by means of theoretical analyse, finite element modal analyse and experiment. The response spectrum of typical impact is generated using dynamic response analysis on various types of pulse waveform, pulse amplitude and pulse width. Based on the function of hard disk assembly, a finite element model of mobile hard disk has been built using penalty method and is validated using sample drop test. Crashworthiness evaluate is set forward based on outer appearance and inner function. Crashworthiness of head actuator arm material, shape and drop angle are studied, which can be taken as practical references for mobile hard disk crashworthiness optimal design.Non-linear mapping relation of key components structure parameters and drop impact response is built using FEM (finite element method) and experimental design. Multiple objective optimization algorithm with crashworthiness is analyzed based on ANN(Artificial Neutral Network)and GA(Genetic Algorithm). Considering drop impact diversity and randomicity, crashworthiness robust design aim at reducing influence of floor rigidity is researched through analyzing controlled variable parameters and noise factor. Key components optimal structure parameters are acquired through taguchi method.Considering drop impact uncertainty and liquid-sold coupled of elasticity fluid-filled container, the finite element analysis and Arbitrary Lagrange-Euler (ALE) algorithm are used here, to analyze the influence of drop parameter and drop impact parameters. Mapping relations of fluid-filled container structure parameter, drop impact parameter and contact point stress are set up based on the FEM and ANN. In theoretically, the results are proven to be fundamental method of crashworthiness analysis, evaluation and design for fluid-filled containers. The method avoids complexity process with building drop impact mathematics model.A drop impact crashworthiness robust design optimize method for manufactured products is developed, which provides us not only a qualitative description but also a quantized description about mobile hard disk and fluid-filled container drop impact in order to enhancing crashworthiness. This research work provides scientific guidance and practical references through a serial of method of parameters selection, experiment design, FEM modeling, dynamic analysis, crashworthiness evaluation, numerical modeling, multiple objective optimization, and robust design.