Study On Mechanical Properties Of Asymmetric Connections In Box House

With the development of the temporary construction market,the box houses have been developing rapidly due to its low cost,convenient transportation,flexible layout and recyclability.The connections of the box house are important parts of the box house,and its structure and force are complicated.However,scholars have little research on the mechanical properties of connections in box house.Therefore,this dissertation combines experimental testing and numerical analysis to study the Stiffness,bending capacity,failure mode and stress state under normal working conditions.The main contents include:(1)The monotonic loading test of a total of 8 types of connections of box-type is carried out.The rotational stiffness,bending capacity and failure mode are studied.The results show that the connections have obvious semi-rigid characteristics,and the initial rotational stiffness and bending capacity of the multi-bolt tension joint specimens are large.The specimen failure is mainly caused by the buckling failure of the corner post.The initial rotational stiffness and the flexural load carrying capacity are small,and the failure of the test piece is mainly caused by the failure of the weld joint connection between the corner post connector and the corner post.(2)Through the comparison between the finite element calculation results and the experimental results,the correctness of the finite element model is verified,and the stress state of the bolts and connectors is analyzed by numerical analysis.The results show that when the multi-bolts are pulled,the L-shaped bolts have the most unfavorable stress on the corner bolts;when the single bolts are pulled,the bolts on the inner side of the joints are the most unfavorable.(3)The influence of the rotational stiffness of the connection on the lateral stiffness of the box house is considered considering the influence of the wall panel and the influence of the wall panel.The results show that in both cases,the connection stiffness of the joint has obvious influence on the lateral stiffness of the box house.The wall panel has a great influence on the lateral stiffness of the box house.When studying the lateral stiffness of the box house,considering the impact of wallboard on it.(4)Through the method of numerical analysis,the maximum stress of the singlelayer,double-layer and three-layer box-type corner pieces under various working conditions is obtained,and three optimization schemes of the corner pieces are proposed according to the stress state of the corner pieces.The results show that the thickness of the upper cover plate and the coaming plate is weakened,the thickness of the lower corner plate is weakened,and the corner piece always meets the requirements of the required stress,and satisfactory results are obtained.