Research On The Key Technology Of The Full-load Compound Environment Simulation Of The Super Large Test Cabin

With the development of China's automobile industry and the continuous growth of production capacity,the requirements for the adaptability of automobile environment are becoming higher and higher.The development of various kinds of automobile environment simulation equipment and technology is in the ascendant.In this paper,aiming at the bottleneck problems of automobile manufacturers in high altitude extreme environment test,such as short single time limit,limited by regional environment and long overall cycle,through the research of large space,large span,high altitude environment simulation technology,the cabin structure of large-scale automobile environment simulation test cabin is designed to meet the requirements of automobile high-altitude environment simulation test and other complex environmental conditions.In this paper,according to the environmental simulation conditions required by the high altitude environmental test cabin,the modular design method from the whole to the local is applied to carry out the design and research of the overall structure of the test cabin and the key structures such as the shell,air duct,heat insulation cabin and insulation structure,the high and low temperature refrigeration and heating scheme,the optimization of the duct contraction section,and the finite element analysis of the test cabin structure.The main contents and results are as follows:(1)Overall design and key structure design of high altitude environment simulation test cabin.By analyzing the test function,working conditions and design requirements of the environment simulation test cabin,the system composition of the test cabin is determined by theoretical analysis combined with practical application research method,and the overall structure design of the test cabin is completed;the key structures of the pressure cabin,air duct structure,pressure bearing door,transition chamber,observation window and the selection of the main materials of the test cabin are designed The main structure to meet the functional requirements of the test cabin is obtained.(2)Thermal insulation design and thermal load analysis and calculation of the test cabin.Through the analysis of the requirements and characteristics of the cabin structure,the appropriate insulation form is designed.The test cabin adopts internalinsulation,and the air duct adopts external insulation.By comparing the thermal insulation materials,the main thermal insulation material is polyurethane,the non pressure bearing structure(such as bulkhead)is made of polyurethane library plate,and the pressure bearing structure(such as bottom plate)is made of 3240 epoxy board and polyurethane to form multilayer board structure.According to the performance requirements,the appropriate refrigeration and heating mode is determined,and the maximum cooling capacity and heating capacity required by the test chamber are determined by thermal load analysis.(3)Structural optimization design of air duct contraction section.According to the windward speed required by automobile test,the structure optimization design of air duct contraction section is carried out to obtain the air flow quality of straight,uniform,stable and large speed to meet the test requirements.After optimization,the maximum upwind velocity of the outlet section can reach 39.282m/s,with good uniformity,and the flow field quality can meet the requirements.The air flow temperature distribution in the high and low temperature heating and cooling of the test cabin is simulated and analyzed,and the influence of different inlet and outlet modes on the temperature distribution uniformity is discussed.The analysis results show that the uniformity of the two-sided inlet and bilateral return air is good,which can meet the requirements of the test chamber.(4)Structural performance analysis of the test cabin under low pressure.Under the negative pressure load,the static analysis,modal analysis and fatigue life analysis are carried out by HyperWorks.The analysis results show that the cabin structure meets the design requirements,and the test cabin maintains good mechanical properties under the working state.The design has application value and can guide the production of the test cabin.