Papers by Author: Li Hui Lang

Abstract: Fiber metal laminates (FMLs) are widely used in aerospace industry due to their unique high specific strength, fatigue resistance, corrosion resistance and other excellent characteristics. Thermosetting FMLs is generally used for forming large size parts and rarely used as raw material for producing small size and complex shape parts. This study attempts a methodology that stamping thermosetting FMLs to form cylinder shape parts before the curing process. The forming limit height of FMLs were analyzed by choosing different core materials, layup direction and skin layer thickness. And through the optimization of these variables, a better-quality part has been formed.

Abstract: Sheet hydroforming process of one irregular box with unequal height and flat bottom was investigated by numerical simulation and experiment. The effect of blank shape and pressure loading path on the forming result was discussed. The key process parameter was optimized. The results have shown that the round blank is the best shape blank. The part can be formed with the appropriate blank shape and die cavity pressure.

Abstract: Selecting an appropriate preloaded coefficient has always been a challenge in wire- winding prestressed structure optimum design. Cased-based reasoning (CBR) has become a successful technique for knowledge-based systems in many domains. However, hardly any research has addressed the issue of how to generate the adaptation solution when the case has been retrieved. The present paper investigates the adoption of genetic algorithm(GA) to explore the suitable adjustment model. Two adapted model were presented and assessed in terms of their mean relative prediction error rates.The experiment results shown that applying GA to adjust the preloaded coefficient selection model is a feasible approach to largely improve the accuracy of estimation model. It also demonstrate that the adapted CBR presents better estimate accuracy than the results ontained by other unadapted CBR methods.

Abstract: The flow behavior and ductility of the Aluminium alloy 5A06 was investigated in the tensile test at the elevated temperatures from 20oC to 300oC and strain rates range of 0.0006s-1 0.06s-1. The influences of strain, strain rate and temperature to elongation strain at fracture , percentage elongation , tensile strength , strain hardening exponent and strain rate sensitive exponent were researched on the basis of experimental stress-strain curves, showing 5A06 is a temperature sensitive alloy. Warm/hot hydromechanical processing of cylindrical cup deep drawing was simulated. It is demonstrated that the differential temperature mode with cool punch and heated die can enhance the forming limit significantly compared with the constant temperature mode of all tools in the same temperature.

Abstract: Sheet hydroforming has drawn much attention in the world because of its many advantages such as high drawing ratio, good surface quality and high dimensional accuracy, less springback etc. Based on the practical needs and the development of the hydroformed production, this paper presents the recent development of the sheet hydroforming and some innovative methods for the equipment, the processes and the numerical analysis methods have been introduced shortly.

Abstract: As one of the oldest manufacturing methods, the plasticity processing still is the basic and important way to produce the components in this period of IT. In the recent years, the plasticity processing has gained more attentions and a further development. At the same time, for the purpose of the sustainable development and the big profit, the environmental friendly methods should be applied into the plasticity processing. Based on the introduction to the development of the precise forging and stamping, this paper described the development trends and the basic needs of the plasticity processing and indicated that it is demanded to speed up the change of plasticity processing from the experimental or trial-and-error types to the scientific analysis and to realize more of precision, more of economy and more of greening (3M strategy) for the processing.