According to poor computational accuracy at small to median sample sizes of Monte Carlo ( MC ) simulation techniques in estimating the probability failure of mechanical structures, the number theoretical net ( NT-net ) simulation method is proposed to reduce computing effort. Several key concepts, such as good point set, good-lattice point ( glp ), discrepancy and NT-net method, are defined. The sampling stategy is improved by introducing NT-net that can provide better convergent rate over MC. The new method is used to estimate failure probability of the side impact bar on the car door. Results indicate the computational effort needed by NT-net for the same accuracy is about 1/12 of that needed by the MC-based method, and the obtained results are more stable.
in order to guarantee the reliability of the hard disk drive data read/write and slider positioning accuracy, the suspension first order bending frequency, first order torsional frequency, first order sway frequency single objective topology optimization model which were based on solid isotropic elastic material penalty (SIMP) method were put forward, and the suspension multi-objective topology optimization model was defined by using the weighted method. Through the topology optimization design the hard disk drive suspension new topological structure was obtained. The results show that hard disk drive suspension single objective and multi-objective topology optimization design objective frequency are large promote than that of the initial design.
In view of complexity internal structure of mobile hard disk and according to the principle of quality equivalent, a finite element model of mobile hard disk was established. Finite element simulation with dropping impact of mobile hard disk was made based on uniform design. A neural network model of nonlinear mapping relations was established between shell thickness,actuator arm thickness, cantilever thickness and pivot bearings stiffness of mobile hard disk with shell stress,disk interface stress and space with head and disk. The difference is less of the prediction values with the ANN(artificial neutral network) and the simulation datum with the FEM(finite element method). This indicates that the method is effective and may provide theory evidence for optimization crashworthiness design.
With the development of computer network and automation technology, network production of NC machine tool has become trend in enterprise. Aim at communicate interface of NC machine tool, a NC machine tool control system design based on CAN bus was presented. Asynchronism serial communication software between DNC host computer with NC system and hardware realization of CAN bus communication and the key technologies for realizing system were discussed in detail.
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