20 5t-22.5m桥式起重机桁架梁主桁架.doc

20/5t-22.5m桥式起重机桁架梁主桁架 结构及工艺设计 摘 要 本次设计采用的方法是许用应力法，即构件的计算应力不得超过许用应力值。主桁架必需满足强度、刚度、稳定性的要求，保证在工作中不能超过规定的挠度值，不能产生失稳及塑性变形。具体内容如下：完成桁架梁主桁架结构设计计算，这一步包括了基本尺寸的确定，再通过绘制桁架各杆件的影响线 为了能够更稳定地承受载荷，本次设计选用具有竖杆的三角形腹杆体系的折线型桁架。所有型钢均采用等边角钢，弦杆选用双角钢，竖杆和斜杆选用单角钢，并且上下弦杆需加垫板。由于主桁架跨度较大，为保证起重机稳定的工作，还需要加拱。另外，弦杆需要用多段型钢拼接而成。焊接方法选用CO2气体保护焊H08Mn2SiA合金钢 关键词，影响线，CO2气体保护焊 Main Truss’s Structure nd Process Design of 20t-22.5m Trussed Crane ABSTRACT Bridge crane is a mechanical device usually used in production workshop、warehouse for lifting and transporting loads, or make-up and installation work, and it make the production process of mechanization and automation, improve the production efficiency. Truss structure has the advantages of light, low cost, transporting and fixing are very convenient, and it is widely used in the main truss’s structure of bridge crane. However, because of truss structure has the disadvantages of complex structure、more welding working、deformation easily, so we must analysis and compiled manufacturing process reasonable in this design. The design method is allowable stress method, in other words, the calculation of stress the structural parts should be not beyond the application of allowable values. The main truss’s structure meet the strength, stiffness and stability requirement, and ensure it can't exceed the allowable deflection value in the work, and it should also avoid instability and the deformation of plasticity. The main elements of this design are as follows： complete the main truss’s structure design by counting, include of determine the basic size, and through drawing influence line of each bars, calculate its size and character, determine its section, and check its stiffness and add arch design. In order to bear loads more stable, the hard dine truss of triangle abdominal rod system with vertical rod are chosen in this design. All payments are used equilateral angles, and the chord choose double angles, vertical rods and sway rods choose single angle, and the c