Modeling Method And Dynamic Characteristics Of Bolt Joints

Bolted joint surface is a very common connecting form of mechanical structural. It has a great influence on the static and dynamic characteristics of the whole mechanical system. So, It is necessary to study the bolted joint surface. For example, study on the feasible finite element analysis method. This paper studies the various finite element models of bolted joint surfaces, and the influences of different finite element models on the finite element analysis results of whole bolted joint surfaces are discussed. The bolted joint surfaces dynamic characteristics of related parameters in different joint surface conditions and the change rule of those dynamic characteristics under the condition of changing the bolt pre-tightening force are in-depth studied.The main contents of this paper can be summarized as following:Firstly, on the basis of consulting a large number of literatures at home and abroad, the current state of studies on joint surfaces has been summarized. This includes the current state of joint surfaces modeling and the status of study on its dynamic characteristic. The joint surface modeling and research results of dynamic characteristics and the exciting deficiencies are discussed.Secondly, within the elastic range, the stiffness calculation formula of bolt and the connected are deduced on the base on bolt pre-tightening solution formula. In view of the non-uniformity of pressure which generated on the joint surfaces, this paper makes a pressure equivalent distribution of the joint surfaces and deduces the solving the formula of equivalent area. Those provide the theoretical guidance to the bolt-joint structure finite element model.Thirdly, the equivalent dynamic model of bolted joint surfaces is established. Virtual equivalent material model of joint surface is proposed on the basis of "solid-gap-solid" model. Using the method of strain energy, this paper deduces the elasticity modulus and poison's ratio of virtual materials of joint surfaces; The thickness and density of virtual materials of joint surfaces are deduced From the perspective of microscopic analysis.Fourthly, making the finite element analysis of bolted joint with different modeling methods, and the advantages and disadvantages and application scope were compared and analyzed. It makes the quantitative or qualitative researches to characteristic parameters of virtual layer and studies the influences the dynamic characteristics on the joint surfaces.Finally, through the test data which obtained by test, this paper checks and evaluates the effectiveness of the finite element model of joint surface which adopted the virtual layer method.