The Finite Element Value Simulation Of Composite Bolt Threaded Nut Contact And Experimental Study

The traditional material to manufacture bolt thread nuts in the rear part of anchor rods is steel. However, steel products cost high, are easy to corrode, are frequently drawn into the synthesis equipment to damage the cutting tool in a coal mining machine, are easy to produce spark when installed. Therefore, this article proposes" replacing steel to manufacture bolt thread nuts in the rear part of anchor rods with glass fiber of reinforced and composite material" in order to solve the problems of joint intensity and rigidity of bolt thread nuts and anchor rods with composite materials. This article takes factors such as the influence of gap size between the external screw thread of an anchor rod and inside cap nut box thread and the influence of cap nut length into account, makes use of finite element analysis software ANSYS to make separate value simulation of touching and finite elements of the stress field and bias field under axial load function during gap coordination between single and double cap nut joints of anchor rod threads with composite materials, to make samples and carry on experiments, and finally make value simulation of finite elements of the stress field and bias field of an anchor rod cap nut body structure under rod axial load function with the utility of finite element analysis software ANSYS.The paper findings indicate that:(1) The cap size of external screw thread of anchor rod and inside screw thread of cap nut box with composite materials exerts little influence on mechanics property of the joint between anchor rod bolt thread and cap nut with composite materials. The choice of cap nut length should contain 8 complete thread teeth, the first three teeth undertake 70% total load, and teeth after the eighty round withstand little load. (2) Changing cap nut structure cannot improve the stress distribution on the anchor, but can improve the stress distribution on the cap nut.On the double nut structure, the stress maximum value on cap nut must be smaller than cap nut of single cap nut structure the distribution should be evener as well. The biggest stress of the joint of bolt thread nut, regardless of single and double cap nut structure with composite materials, occurs at the tooth root of a bolt thread where anchor rod and cap nut contact mutually, and should not surpass the allowable stress according to the coal profession standard request to satisfy the intensity request. The biggest displacement occurs in the load bearing end part of cap nut and satisfies the rigidity request in reasonable distortion scope. The joint of anchor rod bolt thread nut with composite materials meets the utility standard of the coal profession.(3) Experimental results indicate that the greatest supporting capacity of the joint of anchor rod thread cap nut with composite materials is 60 KN (50KN according to the greatest supporting capacity regulated by the coal profession standard plus 20% security quantity) to meet the using standard regulated by the coal profession which further confirms the accuracy of value simulation results.(4) There is stress concentration in the joint of anchor rod cap nut when the body joint of anchor rod cap nut is being loaded and can be improved through choosing the appropriately excessive radius curvature. The bearing capacity of the body joint of anchor rod cap nut must be higher than the joint of anchor rod thread cap nut. However, the infliction of the anchorage force is unable to meet requirements during the actual utility of a project.