Abstract
This paper describes the experimental and theoretical consideration on the load capacity of plastics boltnut joints in the part of thread engagement. Firstly, the tensile tests of the threaded assemblies are carried out to clarify the failure modes and the failure load under some conditions of lubrication, material of nut and temperature. As a result, it is found that there are two different failure modes in the part of thread engagement, that is, shearing and bending of the threads. Secondly, the method to predict the load capacity is proposed for these two failure modes. The main conclusions are as follows : (1) The load capacity of threaded assembly with steel nut is greater than that with plastics nut. (2) When bolt and nut are both plastics, the load capacity decreases by lubricating. (3) The failure modes in the part of thread engagement are influenced by condition of lubrication and rigidity of nut. (4) The values predicted by the proposed method agree fairly well with the experimental results.
