胶合竹片胶层开裂数值模拟研究

为了建立竹材胶合性有限元模型,分析胶合参数对胶合竹集成材性能的影响,为竹集成材数字化优化设计提供参考和指导。应用损伤内聚力单元模型分析胶合搭接竹片,建立竹材胶合开裂数值模型,研究胶接竹片在受载情况下滑剪破坏过程以及搭接长度对胶合竹片承载能力的影响。在位移载荷作用下,开始时胶合层的应力随着弹性变形位移的增加而增加,当达到一定值时胶层开始出现开裂,胶层破坏,且最大应力发生在靠近胶合层边界上;搭接竹片胶合能力随着搭接长度增大而增大。实验结果验证所建数学模型有效,对竹集成材进一步分析和应用提供理论技术支撑。

Research on control method for machining non-cylinder pin hole of piston

The control method for machining non-cylinder pin hole of piston was studied systematically. A new method was presented by embedding giant magnetostrictive material (GMM) into the tool bar proper position. The model is established to characterize the relation between control current of coil and deformation of tool rod. A series of tests on deformation of giant magnetostrictive tool bar were done and the results validated the feasibility of the principle. The methods of measuring magne- tostrictive coefficient of rare earth GMM were analyzed. The measuring device with the bias field and prestress was designed. A series of experiments were done to test magnetostrictive coefficient. Experimental results supplied accurate characteristic pa- rameter for designing application device of GMM. The constitution of the developed control system made up of displacement detection and temperature detection for thermal deformation compensation was also introduced. The developed machine tool for boring the non-cylinder pin hole of piston has the micron order accuracy. This control method can be applied to other areas for machining precision or complex parts.

超磁致伸缩材料器件多目标耦合优化设计

超磁致伸缩材料(Giant magnetostrictive material,GMM)因为具有大应变和热鲁棒性等优良特性而应用广泛。超磁致伸缩材料器件设计中涉及电-磁-机等多个场能量转化,现有的设计主要利用经验公式。针对一种利用GMM智能加工活塞异形孔系统,建立一种综合考虑驱动线圈时间常数、驱动线圈电感、系统一阶固有频率、电磁转化系数及镗杆构件径向变形量为目标的多目标多约束优化设计模型,提出一种耦合有限元计算和非支配排序遗传算法(NSGA-II)计算模型,根据此模型优化结果设计GMM智能加工活塞异形孔系统。所建立的模型及提出的实现方法,对智能化设计GMM器件具有一定的借鉴。