Pure commercial titanium was welded with two types of stainless steel,namely SUS 304 austenitic stainless steel and SUS 821L1 duplex stainless steel.The wavy interface of SUS 821L1 was smaller than that of SUS 304.The...Pure commercial titanium was welded with two types of stainless steel,namely SUS 304 austenitic stainless steel and SUS 821L1 duplex stainless steel.The wavy interface of SUS 821L1 was smaller than that of SUS 304.The vortex zone was observed from both longitudinal and transverse directions,and its composition was analyzed.The interface of Ti/SUS 821L11 was able to bear 401−431 MPa shear load while that of Ti/SUS 304 could withstand 352−387 MPa.The weldability window was used to analyze experimental phenomenon.Furthermore,the smoothed particle hydrodynamics(SPH)numerical simulation method was used to simulate the wavy interface.The trend of wavelength and amplitude change with strength and the stand-offs was consistent with the experimental results.展开更多
Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distribu...Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distributions of thermal and stress fields in the infrared window for hypersonic vehicles based on flowfield studies. A theoretical guidance is provided to evaluate the influence of aerodynamic heating and forces on infrared window materials. The aerodynamic heat flux from Mach 3 to Mach 6 flight at an altitude of 15 km in a standard atmosphere is obtained through flowfield analysis. The thermal and stress responses are then investigated under constant heat transfer coefficient boundary conditions for different Mach numbers. The numerical results show that the maximum stress is higher than the material strength at Mach 6, which means a failure of the material may occur. The maximum stress and temperatures are lower than the material strength and melting point under other conditions, so the material is safe.展开更多
文摘Pure commercial titanium was welded with two types of stainless steel,namely SUS 304 austenitic stainless steel and SUS 821L1 duplex stainless steel.The wavy interface of SUS 821L1 was smaller than that of SUS 304.The vortex zone was observed from both longitudinal and transverse directions,and its composition was analyzed.The interface of Ti/SUS 821L11 was able to bear 401−431 MPa shear load while that of Ti/SUS 304 could withstand 352−387 MPa.The weldability window was used to analyze experimental phenomenon.Furthermore,the smoothed particle hydrodynamics(SPH)numerical simulation method was used to simulate the wavy interface.The trend of wavelength and amplitude change with strength and the stand-offs was consistent with the experimental results.
基金Project supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China （No. 51121004）, and the Fundamental Research Funds for the Central Universities （No. HIT.BRETIV.201315）, China
文摘Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distributions of thermal and stress fields in the infrared window for hypersonic vehicles based on flowfield studies. A theoretical guidance is provided to evaluate the influence of aerodynamic heating and forces on infrared window materials. The aerodynamic heat flux from Mach 3 to Mach 6 flight at an altitude of 15 km in a standard atmosphere is obtained through flowfield analysis. The thermal and stress responses are then investigated under constant heat transfer coefficient boundary conditions for different Mach numbers. The numerical results show that the maximum stress is higher than the material strength at Mach 6, which means a failure of the material may occur. The maximum stress and temperatures are lower than the material strength and melting point under other conditions, so the material is safe.
