scholarly journals Nonlinear Axial Stiffness Characteristics of Axisymmetric Bolted Joints

1990 ◽  
Vol 112 (3) ◽  
pp. 442-449 ◽  
Author(s):  
I. R. Grosse ◽  
L. D. Mitchell

A critical assessment of the current design theory for bolted joints which is based on a linear, one-dimensional stiffness analysis is presented. A detailed nonlinear finite element analysis of a bolted joint conforming to ANSI standards was performed. The finite element results revealed that the joint stiffness is highly dependent on the magnitude of the applied load. The joint stiffness changes continuously from extremely high for small applied loads to the bolt stiffness during large applied loads, contrary to the constant joint stiffness of the linear theory. The linear theory is shown to be inadequate in characterizing the joint stiffness. The significance of the results in terms of the failure of bolted joints is discussed. A number of sensitivity studies were carried out to assess the effect of various parameters on the axial joint stiffness. The results revealed that bending and rotation of the joint members, interfacial friction, and the bolt/nut threading significantly influence the axial stiffness characteristics of the bolted joint. The two-dimensional, axisymmetric finite element model includes bilinear gap elements to model the interfaces. Special orthotropic elements were used to model the bolt/nut thread interaction. A free-body-diagram approach was taken by applying loads to the outer diameter of the joint model which correspond to internal, uniformly distributed line-shear and line-moment loads in the joint. A number of convergence studies were performed to validate the solution.

2004 ◽  
Vol 127 (3) ◽  
pp. 506-510 ◽  
Author(s):  
Ouqi Zhang

It is known that the behavior of real axisymmetric bolted joints in tension is much more complicated than that the conventional theory describes. Phenomenon conflicting with the theory prediction was observed in experimental and finite element analysis [Kwiatkowski, J. K., Winnicki, L. A., and Krzyspiak, A., 1986, “Stress Analysis of Bolted Tensile End Plate Connections,” Rozprawy Inzynierskie Eng. Trans., 34, pp. 113–137; Webjörn, J., 1988, “Die Moderne Schraubenverbindung,” VDI-Z, 130, pp. 76–78; Grosse, I. R., and Mitchell, L. D., 1990, “Nonlinear Axial Stiffness Characteristics of Bolted Joints,” ASME J. Mech. Des., 122, pp. 442–449; Gerbert, G., Bastedt, H., 1993, “Centrically Loaded Bolt Joints,” ASME J. Mech. Des., 115, pp. 701–705]. Recently, a new analytical model of bolted joints was presented [Zhang, O., and Poirier, J. A., 2004, “New Analytical Model for Axisymmetric Bolted Joints,” ASME J. Mech. Des., 126, pp. 721–728], based on which some discussions are further made in this note.


2021 ◽  
Author(s):  
Rashique Iftekhar Rousseau ◽  
Abdel-Hakim Bouzid ◽  
Zijian Zhao

Abstract The axial stiffnesses of the bolt and clamped members of bolted joints are of great importance when considering their integrity and capacity to withstand external loads and resist relaxation due to creep. There are many techniques to calculate the stiffnesses of the joint elements using finite element (FE) modeling, but most of them are based on the displacement of nodes that are selected arbitrarily; therefore, leading to inaccurate values of joint stiffness. This work suggests a new method to estimate the stiffnesses of the bolt and clamped members using FE analysis and compares the results with the FE methods developed earlier and also with the existing analytical models. A new methodology including an axisymmetric finite element model of the bolted joint is proposed in which the bolts of different sizes ranging from M6 to M36 are considered for the analysis to generalize the proposed approach. The equivalent bolt length that includes the contribution of the thickness of the bolt head and the bolt nominal diameter to the bolt stiffness is carefully investigated. An equivalent bolt length that accounts for the flexibility of the bolt head is proposed in the calculation of the bolt stiffness and a new technique to accurately determine the stiffness of clamped members are detailed.


Author(s):  
Raphael Calazans Cardoso ◽  
Brenno Lima Nascimento ◽  
Felipe de Freitas Thompson ◽  
Sandro Griza

The bolted joints sizing procedures shall adequately match the conditions imposed on the joint in service, to ensure high reliability designs. Therefore, this study aims to analyze the load distributions on the bolt when applying external load on bolted joints. Finite element and extensometry analyses as well as analytical calculations were performed in order to compare the magnitude of the joint overall stiffness, with respect to several available theories. The results acquired through the analytical method prescribed in the VDI 2230 standard as well as the finite element and extensometry analyses obtained great accordance. These results indicate that VDI 2230 standard adequately represents the mechanical behavior of the joint and should be used as a guideline for the reliable design of bolted joints subjected to the loading conditions of the present paper.


2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Xianjie Yang ◽  
Sayed A. Nassar ◽  
Zhijun Wu ◽  
Aidong Meng

The nonlinear plastic deformation behavior of a clamped bolted joint model under a separating service load is investigated using analytical, finite element, and experimental techniques. An elastic-plastic model is used for the bolt material while the joint material remains in the linear elastic range. Both the analytical and finite element analysis (FEA) models investigate the variation in the tension of a preloaded bolt due to a separating service load that acts with an offset from the bolt center. Experimental verification is provided for both the analytical and finite element results on the bolt tension variation, clamp load variation and the clamp load loss caused by the incremental plastic bolt elongation under cyclic separating force.


2010 ◽  
Vol 118-120 ◽  
pp. 147-150
Author(s):  
Da Zhao Yu ◽  
Yue Liang Chen ◽  
Yong Gao ◽  
Wen Lin Liu ◽  
Zhong Hu Jia

Three-dimensional finite element model of a cracked bolted joint has been developed in the non-linear finite element code MSC.Marc and attempts were made to validate it by comparing results with those of experiments and other finite element. Issues in modeling the contact between the joint parts, which affect the accuracy and efficiency of the model, were presented. Experimental measurements of load transfer were compared with results from finite element analysis. The results show that three-dimensional finite element model of cracked bolted joint can produce results in close agreement with experiment. Three-dimensional effects such as bolt titling, seconding and through-thickness variations in stress and strain are well represented by such models. Three-dimensional finite element analysis was also used to study the effects of hole mod and crack on the load transfer behaviour of single lap bolted joints. The results show that hole mode has big effect on load transfer of cracked bolted joint. In the whole progress of crack growth, the load transfer through bolt 1 decrease, and almost all of the load duduction of bolt 1 transfer into blot 2 rather than into bolt 3.


2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Sayed A. Nassar ◽  
Xianjie Yang ◽  
Satya Vijay Teja Gandham ◽  
Zhijun Wu

The nonlinear deformation behavior of clamped bolted joints under a separating service load is investigated using finite element and experimental techniques. Although the materials for the bolted joint remain in the linear elastic range, the interface contact area between the clamped plates is sensitive to both the magnitude and the location of the separating force. This often causes nonlinear deformation behavior of the bolted joint. This finite element analysis study investigates the variation in the tension of a tightened bolt and the corresponding change in the joint clamp load due to a separating service load that is placed at various distances from the bolt center. The separating force is symmetrically placed at locations (from the bolt center) that are equal to 3–5 times the nominal diameter of the bolt. Experimental verification of the finite element results is provided.


2010 ◽  
Vol 97-101 ◽  
pp. 3924-3927 ◽  
Author(s):  
Da Zhao Yu ◽  
Yue Liang Chen ◽  
Zhong Hu Jia ◽  
Yong Gao ◽  
Wen Lin Liu

Three-dimensional finite element model of a bolted joint has been developed in the non-linear finite element code MSC.Marc and attempts were made to validate it by comparing results with those of experiments and other finite element. Issues in modeling the contact between the joint parts, which affect the accuracy and efficiency of the model, were presented. Experimental measurements of surface strains and load transfer ratio(LTR) were compared with results from finite element analysis. The results show that three-dimensional finite element model of bolted joint can produce results in close agreement with experiment. Three-dimensional effects such as bolt titling, seconding and through-thickness variations in stress and strain are well represented by such models. Three-dimensional finite element analysis was also used to study the effects of different parameters on the mechanical behaviour of single lap bolted joints. The results show that straight hole, small bolt diameter, and big hole pitch are selected first for bolted joint if other conditions allowed, and effect of bolt material on LTR of joint is small for small load. Interference and pre-stress should be strictly controlled for bolted joints in order to attain the best fatigue capability of lap joint.


2021 ◽  
Vol 13 (4) ◽  
pp. 35-45
Author(s):  
Calin-Dumitru COMAN COMAN

This paper presents the effects of temperature on the axial stiffness of a hybrid metal-composite countersunk bolted joint designed for the bearing failure mode. A detailed 3D finite element model incorporating geometric, material and friction-based full contact nonlinearities is developed to numerically investigate the temperature effects on joint stiffness. In order to validate the temperature effects, experiments were conducted using an Instron testing machine coupled to a temperature controlled chamber. The results showed that the temperature effects on axial joint stiffness were quite accurately predicted by the 3D finite element model, denoting a reduction in the stiffness of the axial joint with an increase in temperature for hybrid metal-composite countersunk bolted joints.


2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.


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