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This paper presents a detailed discussion of the bending properties of laser welded web-core steel sandwich plates and the influence of weld width on stiffness and strength. The over-hanging three point bending test was conducted on the laser welded web-core steel sandwich plates with various welds width by self-designed device, together with the finite element simulations. A good agreement is obtained between the 2D FE analyses and experiment results. The stiffness and strength of the sandwich plates increased with the increasing of weld width, especially for the weld width lower than 60% thickness of the core plate. It is necessary to consider the weld width in the design and evaluation of the stiffness and strength of the laser welded web-core sandwich plate. Base on the results, the FEM is the priority to analysis bending properties of laser welded web-core steel sandwich plates.

All steel laser welded sandwich plates have found their position in the marine and land vehicles. To implement such design accurately, knowledge about its strength properties and the influence of laser weld dimensions on strength is necessary. In this paper, the over-hanging three point bending tests were conducted on the laser welded web-core steel sandwich plate with various weld dimensions by self-designed device, together with the finite element simulations. The results show that the joint is formed on the first plastic hinge when the load is no longer a linear relationship with the deflection, and the joint cracking when the load reaches the maximum bearing capacity of sandwich plate. The joint yield load and the maximum bearing capacity of the sandwich plates increased with the increasing of weld width. Meanwhile, the mode of failure of sandwich plates also changed: When the weld width is smaller, the mode of failure is joint yield, When the weld width is greater than 3mm, the mode of failure is the combination of partial joint yield, face plate and core plate local yield, while the face plate and core plate yield exists in the whole weld joint. It is necessary to consider the weld width in the design and evaluation of the strength of the laser welded web-core sandwich plate.

This paper presents the influence of the weld widthroot gapand weld offset of the T-joint to the overall stiffness of sandwich plate with finite element simulations. From the results of finite element calculation and some of experimental verification we can see:(1) For this structure, welding joint damage occurs before the face plate buckling.(2) Among the factors weld widthgap and weld offset of the T-joint, the weld width affect the overall stiffness the most. (3) When root gap and weld offset lower 0.1mm and 0.12 mm, respectively, they have a little influence on the resistance of deformation ability for the sandwich plate, they can be ignore.

A numerical model has been build up to study temperature evolution and metal flow for the indirect extrusion of 6005A aluminium alloy. Model validation was carried out by comparison between experiments and simulations. Results show a good agreement with each other. The influence of the extrusion parameters on the profile temperature and metal flow were studied according to the real industrialized process. It was found that the profile temperature increases with the ram speed as well as the peak load of the total press force. However, a too slow extrusion process would cause increasing of the total force at the end of the extrusion because of heat dissipation to the environment. In addition the dead metal zone at the top of the billet was shrunk during the extrusion process. The ram speed would have little influence on the distribution and shape changing of dead metal zone. Once the extrusion went into steady stage, the strain rate of metal flow would keep a stable situation relatively.

This paper uses the small punch test (SPT) to some performance of the materials, have put forward basic method to test the material tensile mechanics performance from an inverse FE method with SPT. The research shows that some tensile mechanics performance and stress of each district of welding seam can be accurate determined by small punch test. This research has offered the theoretical foundation for characterizing of the welded joint with mechanical heterogeneity