冷中子孔道方管设计及强度分析

Design and Strength Analyses of Square Tube in Cold Neutron Channel

冷中子孔道方管采用铝合金材料焊接而成,其作用是从冷中子源引出中子。方管既要承受外压,还要做得尽可能薄,以增加中子通量。通过CATIA软件建立方管三维模型,使用Abaqus for Catia计算了方管的强度,计算时对方管采用壳单元。Abaqus for Catia使用CATIA软件建立的模型,在有限元计算时调用ABAQUS程序。为保证计算结果可靠,分别采用整体方管模型和单独计算平板两种方法进行对比计算。计算表明设计厚度为7mm时,能够满足强度要求。由于加工造成厚度减薄后,强度不能满足要求,根据工厂制造经验,对于此类结构,采用"Π"形零件焊接而成,结构更加合理。

Square tube in cold neutron channel is welded together by aluminum alloy plate,it is used to guide neutron from cold neutron source. Not only does the square tube subject to external pressure,but also it is made as thin as possible to increase neutron flux. Using CATIA to build the tube's 3-dimension model and its strength is analyzed in ABAQUS FOR CATIA. Shell element is used in the finite element model. ABAQUS FOR CATIA software uses the model designed in CATIA,during finite element calculation,it calls ABUAQUS software. To ensure the calculation result,two models are used. One is square tube integral model,and the other is separate plate model. The result shows that the designed thickness of 7mm can match the strength requirement. When the square tube becomes thinner because of manufacture error,the strength can't fulfill the requirement. According to the manufacture experiment,' Π ' shape plate is more suitable for square tube structure instead of 4 plates welded together.