Papers by Keyword: Joint Stiffness

Abstract: In the field of modern logistics, assembled steel racks are one of the most widely used structure forms. Hold-welding beams, as the main load-bearing component, were researched in this paper. Firstly, mathematical relationship between semi-rigid joint stiffness K and bearing capacity of hold-welding beams P were derived. Then, hold-welding beams which span were 2300mm, 3000mm, 3300mm and 3600mm were analyzed. When K varies from 0 to 30EI/L, the bearing capacity P was concluded. Finally, the most suitable joint stiffness was concluded respectively in four types of span.

Abstract: Thin walled structure is widely used in designing light weight vehicle. For automotive industry, weight is an important characteristic to increase performance of a vehicle. Vehicle structures are built from thin walled beams by joining them using various joining methods and techniques. For a structure, its stiffness greatly depends on joint stiffness. However, stiffness of thin walled beam is difficult to predict accurately due to buckling effect. Once the beams are joined to form a structure, it will expose to joint flexibility effect. A lot of researches had been done to predict the behaviors of thin walled joint analytically and numerically. However, these methods failed to come out with satisfactory result. In this research work, finite element model for 3D space frame thin walled structural joint is developed using circular beam element by validating with experimental result. Another finite element model using rigid element is used to represent 3D space frame behavior without joint effect. The difference between these 2 models is due to joint effect. By using same modelling technique, joint stiffness for different sizes can be established. Then, the relation between joint stiffness for 3D space frame and size of beam can be obtained.

Abstract: Joint member stiffness in a bolted connection directly influence the safety of a design in regard to both static and fatigue loading as well as in the prevention of separation in the connection. Thus, the accurate determination of the stiffness is of extreme importance to predict the behavior of bolted assemblies. In this paper, An analytical 3D axisymmetric model of bolted joints is proposed to obtain the joint stiffness of Bolted Joints. Considering many different analytical models have been proposed to calculate the joint stiffness, the expression based force equilibrium can be a easy way to choose the best expression for the joint stiffness as a judgment criteria.

Abstract: Reference to the proposed research results and abroad specification, T-beam connection is widely used in engineering steel connection. Comparing with the finite element result, it has been verified that this method can effectively calculate the moment-rotation curve. So it can be a beneficial supplement to the steel structure design code of the T-beam connections.

Abstract: As a new type of joint, the thick-walled steel tubular joint is applied in the single-layer latticed shell to solve the connectivity problem of rectangular tube. In combination with the design of practical project, the effect of the new joint stiffness on the overall stability of a single-layer latticed shell and the value of joint stiffness are studied by ANSYS. Some parameters as the rectangular tube section, the thickness of thick-walled steel tube and connecting plate are taken into account in the process of geometric nonlinear analysis. The results show that joint stiffness has great influence on the overall stability of a single-layer latticed shell and the range of effect gradually increases with the growth of rectangular tube section.

Abstract: Articulated robots are the most common industrial robots for their large workspace and flexibility. However, the existence of joint flexibility makes those robots difficult to achieve high absolute position accuracy. This paper presents a method to identify the joint stiffness of the robot. The basic idea of that method is to get joint stiffness based on Hooks Law through stepping movement of a single joint and calculating the corresponding joint gravity torque of every step. The practicality of that method is verified by experiment and a plan is carried out to compensate the joint flexibility.

Abstract: This paper deals with the formulation and analysis of dynamic mechanism for joint flexibilities whose relevant magnitudes of stiffnesses are investigated by using linear and torsional springs. The equation of motion is derived by using a generic joint in the middle of clamped-clamped beam. A behavior of natural frequency sensitivities is studied as a function of nondimensional linear and torsional spring stiffnesses.

Abstract: In order to evaluate the reliability of vehicle design and vehicle safety performance, analysis software is applied to establish the analysis model of automotive joint stiffness; Body joint stiffness of design vehicles and benchmark vehicles; Reasonable and feasibility of body joint stiffness of design vehicles are verified by comparison.

Abstract: Machine tool joint stiffness has important affects on the dynamic characteristics of the whole machine tool. It is a challenging task to optimize multi-joint stiffness of the overall structure. By discussing the distribution of stiffness of linear guides, ball screws, bolt joints and bearings, a discrete optimization method of multi-joint stiffness of a machining center was presented based on orthogonal experiment and FEA. Mean frequency formulation was adopted to define the index of orthogonal optimization. According to the principle of orthogonal experiment, optimization levels were found out, sequence of the factors on the index of the orthogonal experiment was listed and significant factors were determined. Results of this research proved the validity and feasibility of the discrete optimization method of multi-joint stiffness of the whole machine tool by combining orthogonal experiment and FEA.

Abstract: The bolt-ball joints and welded hollow spherical joints are used frequently in the reticulated structures. Many researches on the influence of the bolt-ball joints stiffness on dynamic and static mechanical behavior of these structures are carried out by far. This paper reviews these researches, and points out the limitation as well, then the future work of which has been put forward. In addition, the progress made in our work team in this filed is illustrated.