With the development of high Mach missile．the radome under the adverse circum-stances needs better high temperature radome material. Nitrides have become the most preponderant candidate for a new generation of high temperature radome material because of the unique comprehensive properties，such as high temperature resistance，high-strength，rain corrosion resistance and low dielectric constant．

  A numerical analysis model of thin-wall outer casing on aeroengine combustion chamber during laser welding is built. Weliding deformations due to circumferential weld of thin-wall outer casing on cunbustion chamer is studied by numerical analysis based on Sysweld. The temperature field, stress field distribution and welding deformation in thin-wall outer casing during laser wilding are simulated. The problem of heat source during welding simulation is analyzed and investigated mathematically.Then the analysis results are qualitatively discussed according to the factual working conditions of whole thin-wall outer shell for validating the feasibility of the analysis method.

The mechanical properties of high-strengh titanium alloy joint are tested. The result show that the welding seam microstructure of Ti17 exhibits needle morphology, with the hardness less than that of the base metal, whereas the microstructurei n the HAZ shows obvious grain grorwth and the hardness higher than that of the base metal．The fraucture of the joint is ductile，witll higIIer elongation than that of the base metal and 75% the fracture strength of the base metal.

Value Engineering (VE) method is applied to the analyze the weapon equipment．The disaggregated structure and calculating method of life circle cost of weapon equipment is put forward．The effectiveness structure of weapon equipment is analyzed and its effectiveness is quentified. On the basis of these studies, the theoretic and practical models of weapon equoment are set up.

To weld and repair the aircraft landing gear by manual TIG welding instead of shielded metal arc welding(SMAW welding)wllich is used in air unit now is tentatively discussed. The best welding technique of TIG welding is obtained after experiments.

A simulation model of the landing gear taxi test is built by using ADAMS/Aircraft taking an carrier type landing gear as an example.The motion formula of the landing gear taxi is given, The as an  simulation analysis of taxi test is carried out. The simulation result is consistent with the theory.