To see the other types of publications on this topic, follow the link: Bolted joint stiffness.
Journal articles on the topic 'Bolted joint stiffness'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Bolted joint stiffness.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Wang, Xi Wang, Xiao Yang Li, Lin Lin Zhang, and Xiao Guang Wang. "A New Approach for Determining Joint Stiffness of Bolted Joints." Applied Mechanics and Materials 670-671 (October 2014): 1041–44. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.1041.
Full textAbstract:
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.
2
Qin, ZY, QK Han, and FL Chu. "Analytical model of bolted disk–drum joints and its application to dynamic analysis of jointed rotor." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 4 (May 9, 2013): 646–63. http://dx.doi.org/10.1177/0954406213489084.
Full textAbstract:
Bolted joints are widely used in aero-engines. One of the common applications is to connect the rotor disks and drums. An analytical model for the bending stiffness of the bolted disk–drum joints is developed. The joint stiffness calculated using the analytical model shows sound agreement with the calculation obtained based on finite element analyses. The joint stiffness model is then implemented into the dynamic model of a simple rotor connected through the bolted disk–drum joint. Finally, the whirling characteristics and steady-state response of the jointed rotor are investigated to evaluate the influence of the joint on the rotor dynamics, where the harmonic balance method is employed to calculate the steady-state response to unbalance force. The simulation results show that the joint influence on the whirling characteristics of the rotor system can be neglected; whereas, the presence of the bolted disk–drum joint may lead to a decrease in the rotor critical speeds due to the softening of the joint stiffness. The proposed analytical model for the bolted disk–drum joints can be adopted conveniently for different types of rotor systems connected by bolted disk–drum joints.
3
Lehnhoff, T. F., Kwang Il Ko, and M. L. McKay. "Member Stiffness and Contact Pressure Distribution of Bolted Joints." Journal of Mechanical Design 116, no. 2 (June 1, 1994): 550–57. http://dx.doi.org/10.1115/1.2919413.
Full textAbstract:
Member stiffnesses and the stress distributions in the bolts and members of bolted joints have been calculated for various bolt sizes, as well as thicknesses and materials of the members. The finite element method has been used to calculate the displacement and the stress distributions in the components of the bolted joint. Using axisymmetric elements, the bolted joint could be analyzed as a two-dimensional problem. Member stiffness ratios were calculated from the finite element results and compared with those calculated by a commonly used theory. The values were approximately comparable (16–30 percent difference) for the assumptions under which the theory was applied. Formulas and dimensionless curves which can be used to estimate the member stiffness ratios for several kinds of bolted joints are presented.
4
Grosse, I. R., and L. D. Mitchell. "Nonlinear Axial Stiffness Characteristics of Axisymmetric Bolted Joints." Journal of Mechanical Design 112, no. 3 (September 1, 1990): 442–49. http://dx.doi.org/10.1115/1.2912628.
Full textAbstract:
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.
5
Zhao, Yongsheng, Hongchao Wu, Congbin Yang, Zhifeng Liu, and Qiang Cheng. "Interval estimation for contact stiffness of bolted joint with uncertain parameters." Advances in Mechanical Engineering 11, no. 11 (November 2019): 168781401988370. http://dx.doi.org/10.1177/1687814019883708.
Full textAbstract:
Bolted joints are elements used to create resistant assemblies in the mechanical system, whose overall performance is greatly affected by joints’ contact stiffness. Most of the researches on contact stiffness are based on certainty theory whereas in real applications the uncertainty characterizes the parameters such as fractal dimension D and fractal roughness parameter G. This article presents an interval estimation theory to obtain the stiffness of bolted joints affected by uncertain parameters. Topography of the contact surface is fractal featured and determined by fractal parameters. Joint stiffness model is built based on the fractal geometry theory and contact mechanics. Topography of the contact surface of bolted joints is measured to obtain the interval of uncertain fractal parameters. Equations with interval parameters are solved to acquire the interval of contact stiffness using the Chebyshev interval method. The relationship between the interval of contact stiffness and the uncertain parameters, that is, fractal dimension D, fractal roughness parameter G, and normal pressure, can be obtained. The presented model can be used to estimate the interval of stiffness for bolted joints in the mechanical systems. The results can provide theoretical reference for the reliability design of bolted joints.
6
Lu, Shi-kun, Deng-xin Hua, Yan Li, Fang-yuan Cui, and Peng-yang Li. "Stiffness Calculation Method and Stiffness Characteristic Analysis of Bolted Connectors." Mathematical Problems in Engineering 2019 (August 28, 2019): 1–11. http://dx.doi.org/10.1155/2019/6206092.
Full textAbstract:
At present, few scholars have studied the effect of surface roughness on assembly stiffness. The influence of the joint surface stiffness on the overall stiffness is neglected. In this paper, a new method for calculating the stiffness of bolted joints is presented. The effect of joint surface stiffness on the overall stiffness is considered. Firstly, the relationship between load and displacement between cylinder and cylinder (including the joint surface with certain roughness) is studied, and the stiffness characteristic expression of the joint surface is obtained; the results are compared with the traditional stiffness calculation theory, and then, the influence of bolt connection surface on bolt connection is studied and compared with the stiffness calculation results of traditional bolt connection. The results show that the theoretical model presented in this paper is more practical.
7
Cabaleiro, Manuel, Carlos Moutinho, Cristina González-Gaya, Elsa Caetano, and Victor Fco Rosales-Prieto. "Analysis of Stiffness of Clamped Joints versus Bolted Joints in Steel Structures by Means of Accelerometers and Shaking Table Tests." Sensors 21, no. 14 (July 13, 2021): 4778. http://dx.doi.org/10.3390/s21144778.
Full textAbstract:
This work analyzes the difference in stiffness in a steel laboratory structure using clamped joints or bolted joints and analyzes if the stiffness varies in the same way when the frame is subjected to external dynamic loads that bring the joint materials to their yield strength. To make this comparison, the differences between clamp joint and bolted joint were evaluated using a novel methodology based on the analysis of the structure’s natural frequencies from accelerometers. To perform this comparison, several laboratory tests were carried out on a frame made by clamped joints and the same frame made by bolted joints, using a set of tests on a medium-scale shake table for this purpose. The results achieved have verified the methodology used as adequate.
8
Guo, Tie Neng, Bin Song, Dong Liang Guo, and Zhong Qing Chen. "Dynamic Stiffness Identification of Bolted Joints." Advanced Materials Research 291-294 (July 2011): 1582–88. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1582.
Full textAbstract:
The joint has a significant effect on the dynamic characteristic of the mechanism, and the identification of the stiffness of the joints has become a key problem. In this paper, a method is presented for identifying the dynamic characteristic of joints. An experiment is designed to test the dynamic parameter of the bolted joints specimen; the identification method, based on experiment, has a high accuracy result. By taking a specimen to experiment and identify the dynamic characteristic of joints, the relationship between the preload on the bolts and the joints stiffness is acquired. In order to validate the accuracy of the result, the FEM software is used to simulate. There are only a small discrepancy between the results of identification and simulation.
9
Zhai, Xue, Cheng-Wei Fei, Jian-Jun Wang, and Xing-Yu Yao. "Parametric modeling and updating for bolted joints of aeroengine casings." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 16 (August 9, 2016): 2940–51. http://dx.doi.org/10.1177/0954406215607900.
Full textAbstract:
To establish accurate finite element (FE) model of bolted joint structures of aeroengine stator system (casings), this work implements the parametric FE modeling and updating of bolted joints of aeroengine stator system with multi-characteristic responses (multi-object). Firstly, the parametric FE modeling approach of bolted joint structure was developed based on the thin layer element method. And then the FE model updating thought of aeroengine stator system was developed based on the probabilistic analysis method. Finally, the parametric modeling and updating of the bolted joints of aeroengine stator system with multi-characteristic responses was completed by the optimization iteration calculation of objective function based on the proposed methods and the static stiffness testing data. Through the parametric modeling of bolted joint structures based on the thin layer method, the complexity of FE model of aeroengine casings with many bolted joint structures is reduced. As shown in the FE model updating of casings with multi-characteristic responses analysis, the static stiffness from the updated model are very close to the test data, in which the maximum relative error decreases to 3.9% from 30.52% and the others are less than 3%, so that the design precision of aeroengine stator system with the many and wide variety of bolted joints gets a great improvement. Moreover, the proposed methods of parametric modeling and model updating for multi-characteristic responses are validated to be effective in the simulation and equivalent of the mechanical characteristics of bolted joints in complex systems like aeroengine stator system.
10
Zhang, Ouqi, and Jason A. Poirier. "New Analytical Model of Bolted Joints." Journal of Mechanical Design 126, no. 4 (July 1, 2004): 721–28. http://dx.doi.org/10.1115/1.1760777.
Full textAbstract:
The conventional theory of bolted joints adopts equivalent cylinders, cones or spheres for compression members. In this model, the member deformation is determined by the member stiffness that remains unchanged whether the external load is present. In fact, the external load causes an additional member deformation that is not determined by the member stiffness measured at pre-load. The external load also causes a member rotation, which not only reduces the member stiffness, but also delays the separation of the joint. Based on these observations, a new model of bolted joints is developed. Finite element analyses is performed to verify the proposed model.
11
Cardoso, Raphael Calazans, Brenno Lima Nascimento, Felipe de Freitas Thompson, and Sandro Griza. "Study of bolted joint axial stiffness using finite element analyses, experimental tests, and analytical calculations." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 23 (May 23, 2020): 4671–81. http://dx.doi.org/10.1177/0954406220927066.
Full textAbstract:
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.
12
Lehnhoff, T. F., and W. E. Wistehuff. "Nonlinear Effects on the Stiffness of Bolted Joints." Journal of Pressure Vessel Technology 118, no. 1 (February 1, 1996): 48–53. http://dx.doi.org/10.1115/1.2842162.
Full textAbstract:
Axisymmetric finite element modeling of bolted joints was performed to show the effects of the magnitude and position of the external load, member thickness, and member material on the bolt and member stiffnesses. The member stiffness of the bolted joint was found to decrease 10 to 42 percent for the 20-mm to 8-mm bolts, respectively, as the magnitude of the external load was increased. Member stiffness appears to be independent of the radial location of the external load and increases as the member thickness decreases. Member stiffness decreased by a factor of 2.5 to 3 with a change in the member material from steel to aluminum. The cast iron members had a decrease in member stiffness of a factor of 1.7 to 1.9. The aluminum over cast iron combination had a member stiffness between the aluminum and cast iron alone. Bolt stiffnesses varied by less than two percent for changes in the magnitude of the external load for all bolt sizes and member materials, except for the 8-mm bolt where stiffness increased by approximately 11 percent. Changes in radial position of the external load had no effect on the bolt stiffness. A 3 to 13-percent decrease in the bolt stiffness was found when changing from steel to aluminum members. A 2 to 3-percent bolt stiffness decrease resulted when the member material was changed from steel to cast iron and similarly from steel to the aluminum over cast iron combination
13
Zhang, Z., Y. Xiao, YQ Liu, and ZQ Su. "A quantitative investigation on vibration durability of viscoelastic relaxation in bolted composite joints." Journal of Composite Materials 50, no. 29 (July 28, 2016): 4041–56. http://dx.doi.org/10.1177/0021998316631810.
Full textAbstract:
Time-dependent behavior and factors affecting preload relaxation in a carbon/epoxy composite bolted joint under resonance were studied. The effect of viscoelasticity of composite material on bolt relaxation was studied quantitatively through modal analysis from the perspective of energy dissipation and stiffness degradation. Damping ratio and resonance frequency were utilized to characterize the effects of preload relaxation on structural dynamic response. The loss of preload was found to decrease with increasing initial preloads over a 10 h vibration fatigue. However, an increase in preload loss occurred as exciting frequency increases. Vibration fatigue damage was found to result in decaying stiffness and amplitude responses of the bolted joints, along with an increase in damping ratio. As a proof-of-concept study, a beam-like specimens with and without bolted joints were comparatively excited to ascertain their respective dynamic responses; results revealed that relaxation in bolted joints could be attributed to the conjunct mechanisms between viscoelastic behavior of polymer matrix composites and interface friction for different contact surfaces, where such relaxation behavior was mainly due to viscoelasticity of the joint materials.
14
Jadee, Khudhayer J., and A. R. Othman. "Fiber Reinforced Composite Structure with Bolted Joint – A Review." Key Engineering Materials 471-472 (February 2011): 939–44. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.939.
Full textAbstract:
Fiber reinforced composite structures are widely used in the aerospace, aircraft, civil and automotive applications due to their high strength-to-weight and stiffness-to-weight ratios and these applications require joining composite either to composite or to metal. There are three main methods for joining composite structures namely, bonding, mechanically fastened or a combination of the two. Bolted joint are preferred in structures where the disassembly is required for the purpose of maintenance and repair. Due to the stress concentration around the holes, bolted joints often represents the weakest part in the structure, and therefore it is important to design them safely. A review on the study of bolted joints in fiber reinforced composite structure is presented. It was found that the behavior of bolted joints in composite structure is affected by many factors, such as geometry, joint material, clamping–load provided by the bolts, ply orientations, etc. Accordingly, various researches have been conducted on the analyses of stress distribution, failure prediction, and strength properties of bolted joint both experimentally and numerically. Accurate prediction of stresses in bolted joints is essential for reliable design of the whole structure; if it is not optimally designed, premature and unexpected failures may be occurred.
15
Cheng, Liang, Qing Wang, and Yinglin Ke. "Experimental and numerical analyses of the shimming effect on bolted joints with nonuniform gaps." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 11 (October 30, 2018): 3964–75. http://dx.doi.org/10.1177/0954406218809139.
Full textAbstract:
In order to investigate the effect of shim compensation for nonuniform gaps in aircraft assembly, the influence of the shims with different material and parameters on bolted joints is studied in this paper. According to the real material and assembly conditions of the aircraft joint structures, the specimen and experiment are designed to obtain the tensile performance of the joint structures with different shims. A three-dimensional finite element model, which incorporates the Johnson–Cook material property of the alloys, traction-separation law of liquid shims, contact relationships between the joint elements, and boundary conditions of the tensile process, is established with the specimen configurations. After validating through comparing with the experimental results, the modeling method is adopted to simulate the tensile response of the bolted joints with shims. Furthermore, both the influence of the shim material and thickness on the mechanical behaviors of bolted joints is investigated in detail. Shims can considerably reduce the assembly stress of joint structures and improve the joint stiffness and load capacity, and this effect is more remarkable with the increase of gap values. Liquid shims improve the joint stiffness due to its cohesive ability, while solid shims improve the joint load capacity. Hybrid shims possess a composite shimming effect of liquid and solid shims. Whatever the shim material is applied, the joint stiffness and strength drop with the growth of shim thickness, so strict deviation control method should be taken to ensure the assembly gaps as small as possible. The research results enhance the knowledge of shimming effect on joint structures, and thus offer positive guidance for practical application in aircraft assembly.
16
Liao, Xin, Jianrun Zhang, and Xiyan Xu. "Analytical Model of Bolted Joint Structure and Its Nonlinear Dynamic Characteristics in Transient Excitation." Shock and Vibration 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/8387497.
Full textAbstract:
The dynamic response of crucial components often depends upon the dynamic behavior of bolted connections. As is usually the case, the accurate modeling of structures with many mechanical joints remains a challenge work. The nonlinear behavior included in assembled structures strongly depends on the interface properties. In this paper, an analytical model of the simple bolted joint beam in tangential direction is first proposed for transient excitation, based on phenomenological model. The fourth-order Runge-Kutta method is employed to calculate the transient response, where the dynamic response of the nonlinear stiffness on system is also investigated. The simulation results show that natural frequency has a certain dependence on cubic stiffness term and cubic stiffness is more suitable for modeling of nonlinear system of a wider frequency range. Thereby, a series Iwan model containing cubic stiffness term is established to describe nonlinear behaviors of bolted joint beams in shear vibration. The amplitude-frequency curves show that the influence of interaction between nonlinear stiffness and damping mechanism on dynamic response characteristics is more obvious. Finally, a new type of nonlinear model is applied into finite element analysis. The results of proposed transient excitation experiment are discussed qualitatively, indicating that nonlinear effects observed agree with the numerical simulation results.
17
Ai, Yan Ting, Yan Bai, Xue Zhai, and Dan Zhao. "Finite Element Simulation in the Dynamics Calculation of Bolted-Joint Interface." Applied Mechanics and Materials 215-216 (November 2012): 1009–12. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.1009.
Full textAbstract:
Many components in modern mechanical structure are connected with bolts, and the behaviour of joints significantly affects the dynamic response of these structures. Based on the software of MSC. patran, firstly, a linear dynamic model for bolted joints and interface is developed. The joint interface is modeled using a technology of interface layer element(ILE) and multi-point constrains(MPC) technique. And then, using the MATLAB language, the properties of ILE material are optimized to simulate the bolted-joint interface stiffness. The material properties parameters are identified by using experimental data. This work takes aero-engine case model as an example, researching its model analysis under different pre-stress conditions to check the method and provide insight on how to model the joint interface in the dynamics calculation of bolted structure.
18
Cheng, Bo, and Zhenyu Wu. "Finite Element Analysis on Tensile Stiffness of Cold-Formed Steel Bolted Connections." Open Civil Engineering Journal 9, no. 1 (September 23, 2015): 724–35. http://dx.doi.org/10.2174/1874149501509010724.
Full textAbstract:
This paper presents a finite element analysis on the tensile stiffness of steel bolted connections which are fabricated from thin-walled cold-formed steel strips and their members. This type of bolted connection is usually used to assemble the diagonal bracing member in the light steel structure. Unlike the architectural steel structure, thin walled steel bolted connection cannot be simplified into a hinge joint due to the weak tensile stiffness of connection. The calculation of tensile stiffness of bolted connection is necessary to accurately evaluate the effectiveness of bracing system in the coldformed steel structure. Based on the existing test results and analysis results, finite element (FE) models with threedimensional solid elements were established to investigate the tensile stiffness of bolted connections between cold-formed steel plates under shear. The analysis with non-linear material and contact elements was carried out in order to predict the load-displacement relationships of bolted connections. Furthermore, a parametric study on single-bolted or two-bolted connections with different configurations was performed to study the relationship of connection tensile stiffness and structural parameters such as bolt diameter, plate thickness and steel yield strength. According to the stiffness results obtained from parametric study, six calculating equations for practical design of cold-formed steel bolted connection have been proposed. The calculation results of the stiffness equations are in a good correlation with those of FE analysis, and the proposed equations have been found to provide estimates of tensile stiffness of bolted connections with reasonable accuracy.
19
Zhao, Yongsheng, Jingjing Xu, Ligang Cai, Weimin Shi, and Zhifeng Liu. "Stiffness and damping model of bolted joint based on the modified three-dimensional fractal topography." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 2 (November 14, 2016): 279–93. http://dx.doi.org/10.1177/0954406216631577.
Full textAbstract:
The machine tools are consisted of many parts and most of them are connected by the bolts. Accurate modeling of contact stiffness and damping for bolted joint is crucial in predicting the dynamic performance of machine tools. This paper presents a modified three-dimensional fractal contact model to obtain the stiffness and damping of bolted joint. Topography of the contact surface of bolted joint is fractal featured and determined by fractal parameters. Asperities in microscale are considered as elastic, elastic–plastic, and full plastic deformation. The expand coefficient ψ is introduced to the size-distribution function of asperities. The real contact area, contact stiffness, and damping of the contact surface can be calculated by integrating the microasperities. The relationship of contact stiffness, damping, fractal dimension D, and fractal roughness parameter G can be obtained. Experiments are conducted to verify the efficiency of the proposed model. The results show that the theoretical mode shapes are in good agreement with the experimental mode shapes. The relative errors between the theoretical and experimental natural frequencies are less than 3.33%, which is less than those of the W-K model and L-L model. The presented model can be used to accurately predict the dynamic characteristic of bolted assembly in the machine tools.
20
Wang, Yihuan, Zhan Wang, Jianrong Pan, Peng Wang, JianGui Qin, and Shizhe Chen. "Cyclic Behavior of Anchored Blind-Bolted Extended End-Plate Joints to CFST Columns." Applied Sciences 10, no. 3 (January 30, 2020): 904. http://dx.doi.org/10.3390/app10030904.
Full textAbstract:
As the square steel tube in the tension zone is always the weakest part of moment-resisting joints, modified blind bolts (Hollo-Bolts) and a locally strengthened steel tube in the panel zone were adopted to enhance the joint performance. Cyclic loading tests were carried out on eight anchored blind-bolted extended end-plate joints between square concrete-filled steel tube (CFST) columns and steel beams. The test parameters included the end-plate thickness, steel tube wall thickness, beam section size, local strengthening connection method, blind bolt anchorage method, and stiffeners. The failure mode, hysteretic behavior, stiffness, strength, ductility, strength degradation, stiffness degradation, and energy dissipation capacity of the joints were studied and analyzed. The test results showed that the application of anchored blind bolts and a locally strengthened steel tube can fully utilize the bolt strength and significantly improve the joint performance, especially in terms of strength and strength degradation. The test observations revealed three typical failure modes for the joints, and the failure mode depended on the weakest component. In addition, the local reinforcement of C-channel and change in the anchorage method had a limited effect on the initial stiffness. Greater end-plate thickness and the use of stiffeners significantly increased the joint stiffness and decreased the rate of stiffness degradation. The use of stiffeners also significantly enhanced the ductility and energy dissipation by moving plastic hinge outward from the joints. Finally, finite element analysis (FEA) models were developed and validated against the experimental results, and the stress distribution and force transfer pattern were investigated.
21
Wang, R., A. D. Crocombe, G. Richardson, and C. I. Underwood. "Energy dissipation in spacecraft structures incorporating bolted joints with viscoelastic layers." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 222, no. 2 (February 1, 2008): 201–11. http://dx.doi.org/10.1243/09544100jaero259.
Full textAbstract:
The energy dissipation capacity of bolted joints with viscoelastic layers in a spacecraft structure was investigated. Initially, a linear spring dashpot model was used to represent the bolts in a satellite structure. A relationship was developed between the model parameters (stiffness and damping coefficient) and the viscoelastic material and geometric properties (shear modulus, loss factor, operating area, and thickness) of the actual bolted joint. This model was then developed into the non-linear domain. Experiments on bolted joints with viscoelastic layers were carried out to provide information for the non-linear joint model. These models were incorporated into a simple spacecraft model to investigate the effect on the spacecraft response. Based on these numerical analysis, it was found that the joints can dissipate much energy and the response of the spacecraft structure to vibrations during launch can be decreased significantly.
22
Liu, Xin, Bei Bei Sun, Jian Dong Chen, Fei Xue, and Ren Qiang Jiao. "Experimental Investigation of Dynamics of Assembly with Typical Mechanical Joint." Key Engineering Materials 693 (May 2016): 324–31. http://dx.doi.org/10.4028/www.scientific.net/kem.693.324.
Full textAbstract:
Mechanical joints have a significant influence on the dynamics of assembled structure due to its discontinuity, uncertainty, frictional contact and micro-slip along the interface. To study the effect of mechanical interface on vibration behavior of industrial product, it is necessary to capture vibration data and investigate modal properties. In order to study effects of typical mechanical joints, double plates coupled with bolted joint are manufactured. Corresponding welded specimen was also manufactured for comparison and reference. Specimens were suspended by two flexible nylon cords for a free–free boundary condition and series of modal tests were carried out. Experimental results reveal that the preload in bolted joint affects the vibration behavior of assembly greatly, and the dynamic stiffness and natural frequency could be enhanced by increasing preload values of specimen. Bolted joints give rise to more frictional damping capacity within lower preload range in this test and welded specimen shows up much higher frequency and similar damping ratio.
23
Xu, De Liang, Wei Qing Liu, Ding Zhou, Jian Dong Ding, Ying Lei, and Wei Dong Lu. "The Study on Mechanical Properties of Single-Bolted Steel-Glulam-Steel Joints." Advanced Materials Research 255-260 (May 2011): 204–8. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.204.
Full textAbstract:
Seven groups, total of 31 single-bolted steel-glulam-steel joints, were tested for their mechanical performance. The mechanical properties of single-bolted steel-glulam-steel connection subjected to a load parallel to the grain have been studied. The failure mode and failure mechanism of bolted connections were discussed in detail. It is shown that the failure mode, bearing capacity, stiffness and ductility of the joint are mainly relative to the thickness of the glulam and the diameter of the bolt. Due to the wide application of bolted steel-glulam-steel connections in engineering, the present work can be taken as a reference in manufacture, and design of modern timber structures.
24
Zhang, Jing, Zhi-Fang Liu, Yong Xu, Mai-Li Zhang, and Liu-Cheng Mo. "Cyclic Behavior and Modeling of Bolted Glulam Joint with Cracks Loaded Parallel to Grain." Advances in Civil Engineering 2021 (March 11, 2021): 1–16. http://dx.doi.org/10.1155/2021/6612886.
Full textAbstract:
Under varying humidity and temperature conditions, with the constraint of metal fasteners to wood shrinkage, cracks along the bolt lines are generally observed in bolted glulam joints. A three-dimensional (3D) numerical model was established in software package ANSYS to investigate the cyclic behavior of bolted glulam joints with local cracks. A reversed cyclic loading was applied in the parallel-to-grain direction. The accuracy of numerical simulation was proved by comparison with full-scale experimental results. Typical failure modes were reproduced in the numerical analysis with the application of wood foundation zone material model and cohesive zone material model. The effect of crack number and length on the hysteretic behavior of bolted glulam joints was quantified by a parametric study. It was found that initial cracks impair the peak capacity and elastic stiffness of bolted glulam joints significantly. More decrease in capacity was observed in joints with more cracks, and longer cracks affect elastic stiffness more dramatically. Moreover, with the existence of initial cracks, the energy dissipated and equivalent viscous damping ratio of bolted joints are reduced by 24% and 13.3%, respectively.
25
Terracciano, Giusy, Gaetano Della Corte, Gianmaria Di Lorenzo, and Raffaele Landolfo. "Design Tools for Bolted End-Plate Beam-to-Column Joints." Journal of Engineering 2018 (July 5, 2018): 1–11. http://dx.doi.org/10.1155/2018/9689453.
Full textAbstract:
Predicting the response of beam-to-column joints is essential to evaluate the response of moment frames. The well-known component method is based on a mechanical modelling of the joint, through joint subdivision into more elementary components subsequently reassembled together to obtain the whole joint characteristics. Significant advantages of the component method are the following: (i) the mechanics-based modelling approach; (ii) the easier general characteristics of components. However, the method is commonly perceived by practicing engineers as being too laborious for practical applications. Within this context, this paper summarizes the results of a theoretical study aiming to develop simplified analysis tools for bolted end-plate beam-to-column joints, based on the Eurocode 3 component method. The accuracy of the component method was first evaluated, by comparing theoretical predictions of the plastic resistance and initial stiffness with corresponding experimental data collected from the available literature. Subsequently, design/analysis charts were developed through a parametric application of the component method by means of automatic calculation tools. They are easy and quick tools to be used in the first phases of the design process, in order to identify joint configurations and geometrical properties satisfying specified joint structural performances. The parametric analysis allowed also identifying further simplified analytical tools, in the form of nondimensional equations for predicting quickly the joint structural properties. With reference to selected geometries, the approximate equations were verified to provide sufficiently accurate predictions of both the stiffness and the resistance of the examined beam-to-column joints.
26
Zhao, Shuyuan, Jianglong Dong, Chao Lv, Zhengyu Li, Xinyang Sun, and Wenjiao Zhang. "Thermal Mismatch Effect and High-Temperature Tensile Performance Simulation of Hybrid CMC and Superalloy Bolted Joint by Progressive Damage Analysis." International Journal of Aerospace Engineering 2020 (March 11, 2020): 1–14. http://dx.doi.org/10.1155/2020/8739638.
Full textAbstract:
The hybrid CMC and superalloy bolted joints have exhibited great potential to be used as thermostructural components of reusable space transportation systems, given the respective strengths of these two materials. In the high temperature excursion of the hybrid joints with the aircrafts and space vehicles, the substantial difference in thermal expansion coefficients of CMC and superalloy materials will induce complex superposition of initial assembly stress, thermal stress, and tensile stress around fastening area, which might lead to unknown failure behavior of joint structure. To address this concern, a finite element model embedded with progressive damage analysis was established to simulate the thermostructural behavior and high-temperature tensile performance of single-lap, single-bolt C/SiC composite and superalloy joint, by using the ABAQUS software. It was found that the initial stiffness of the CMC/superalloy hybrid bolted joints decreases with the rise of applied temperature under all bolt-hole clearance levels. However, the load-bearing capacity varies significantly with the initial clearance level and exposed temperature for the studied joint. The thermal expansion mismatch generated between the CMC and superalloy materials led to significant changes in the assembly preload and bolt-hole clearance as the high-temperature load is applied to the joint. The evolution in the thermostructural behavior upon temperature was then correlated with the variations in stiffness and failure load of the joints. The provided new findings are valuable for structural design and practical application of the hybrid CMC/superalloy bolted joints at high temperatures in next-generation aircrafts.
27
Zhang, Xizhi, Jiashu Hao, Dongchao Duan, Shengbo Xu, Shaohua Zhang, and Houxin Yu. "Experimental study on bolted and anchored beam-to-column joints of prefabricated concrete frames." Advances in Structural Engineering 23, no. 2 (August 29, 2019): 374–87. http://dx.doi.org/10.1177/1369433219872432.
Full textAbstract:
A new type of beam-to-column joint used in prefabricated concrete frames was proposed in this study. In this joint, the longitudinal bars at the top of the beam are anchored to the column using straight thread sleeves, and the bars at the bottom are welded to the steel fastener that is bolted to the column. Cyclic loading tests of three specimens, namely, two beam–column joints of this type and a cast-in-place beam–column joint, were conducted to study the seismic behavior and feasibility of this type of joint. The difference between the two prefabricated joints is the shape of the holes on the end plate. Failure modes of the specimens were observed and analyzed. The hysteretic curves, bearing capacities, stiffness degeneration, ductility, and energy-dissipating capacities of the specimens were compared and studied. Test results indicated that all beam–column joints exhibited beam hinge failure. No slippage was observed between the concrete and horizontal plates of the steel fasteners used in the new type of joint. The bearing capacity and initial stiffness of both prefabricated specimens compared with the cast-in-place ones were increased. The steel fastener could increase the distance between the plastic hinge and the side surface of the column while enlarging the length of the plastic hinge. The trend of energy dissipation and stiffness degeneration of the specimens were similar, and the ductility coefficient ranged from 2.7 to 4.91. The displacement angles of the joints exceeded 1/50 before the failure of the specimens. The mechanical behavior of both prefabricated joints was similar, but the joint with U-shaped holes on the end plate was convenient to create.
28
Zhang, Ai Ping, Dong Mei Zhang, and Zhi Feng Liu. "Experimental Study of the Bolted Joint Surface Contact Angle." Advanced Materials Research 765-767 (September 2013): 181–84. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.181.
Full textAbstract:
We will study the effective value of the angle which affect on the bolted joint surface by the experimental research method. It gets the effective angle under different conditions in the experiment by the way of researching the joint surface stiffness which changing during the joint surface area changing in the paper. This results provide valid reference for the mechanical structure design which with the bolted joint surface, so as to achieving the purpose of more efficiency during the mechanical structure design.
29
Lehnhoff, Terry F., and Bradley A. Bunyard. "Effects of Bolt Threads on the Stiffness of Bolted Joints." Journal of Pressure Vessel Technology 123, no. 2 (June 29, 2000): 161–65. http://dx.doi.org/10.1115/1.1319504.
Full textAbstract:
Axisymmetric finite element analysis (FEA) was performed on bolted joints to determine the effects of the threads on the bolt and member stiffnesses. For steel members, the member stiffness decreased 37.1, 37.7, 38.2, 41.0, and 49.4 percent for the 24, 20, 16, 12, and 8-mm-dia bolts, as the magnitude of the external load was increased. The external load was increased from zero to the value that caused the bolt force to equal its proof strength. The member stiffness for aluminum members decreased by 22.7 and 29.9 percent for the 24 and 20-mm bolts. The cast iron members had decreases of 26.9 and 32.3 percent for the 24 and 20-mm bolts. Likewise, the aluminum/cast iron members decreased in stiffness by 25.5 and 30.0 percent for the 24 and 20-mm bolts. The member stiffness with no external load applied decreased by approximately 65 percent when changing from steel to aluminum members, 53 percent from steel to cast iron, and 60 percent from steel to aluminum/cast iron. Bolt stiffness varied less than 1.4 percent over the total range of the externally applied load for each of the bolted joint models. The decrease in bolt stiffness for the 24 and 20-mm-dia bolts was approximately 4 percent when changing from steel to aluminum members, 7 percent when changing from steel to cast iron members, and 8 percent when changing from steel to aluminum/cast iron members. Comparison is made to research results which did not include the influence of the threads.
30
Liao, Xin, and Jian Run Zhang. "Energy Balancing Method to Identify Nonlinear Damping of Bolted-Joint Interface." Key Engineering Materials 693 (May 2016): 318–23. http://dx.doi.org/10.4028/www.scientific.net/kem.693.318.
Full textAbstract:
The interface of bolted joint commonly focuses on the research of non-linear damping and stiffness, which affect structural response. In the article, the non-linear damping model of bolted-joint interface is built, consisting of viscous damping and Coulomb friction. Energy balancing method is developed to identify the dry-friction parameter and viscous damping factor. The corresponding estimation equations are acquired when the input is harmonic excitation. Then, the vibration experiments with different bolted preloads are conducted, from which amplitudes in various input levels are used to work out the interface parameters. Also, the fitting curves of dry-friction parameters are also obtained. Finally, the results illustrate that the most interface of bolted joint in lower excitation levels occurs stick-slip motion, and the feasibility of the identification approach is demonstrated.
31
Lampeas, G., and N. Perogamvros. "Analysis of composite bolted joints by a macro-modelling approach." International Journal of Structural Integrity 7, no. 3 (June 13, 2016): 412–28. http://dx.doi.org/10.1108/ijsi-07-2015-0023.
Full textAbstract:
Purpose – The purpose of this paper is the development and the assessment of detailed and macro-modelling methodology approaches, suitable for the analysis of composite material bolted joints. Design/methodology/approach – A benchmark single-lap, single-bolt composite joint configuration is investigated, in order to demonstrate the different joint analysis approaches which are applicable in advanced riveted/bolted parts of aeronautical structures. In particular, several joint macro-models, i.e. numerical and analytical ones, as well as a detailed three-dimensional FE solid joint representation, were developed and compared in terms of stiffness prediction, while they were validated using respective experimental results. In addition, the numerical macro-model is implemented in a full scale, multi-bolt fuselage panel in order to demonstrate its capability to efficiently predict the panel’s response under compressive loads. Findings – Good correlation was observed between the majority of the models’ predictions and the relative experimental data regarding the lap joint configuration, while the simplified numerical macro-model showed some discrepancies due to the contact instabilities, which, however, may be accepted taking into account the remarkable solution time reductions. In the same manner, the FE macro-model illustrates sufficient accuracy in the prediction of the panel’s response, while, simultaneously, it maintains a low CPU time. Originality/value – The present study is part of Nikolaos Perogamvros’ doctoral thesis, an original research work. There are very limited literature papers which include the development and the assessment of different efficient and detailed composite joint analysis approaches, regarding their accuracy and efficiency in the stiffness prediction of a composite bolted joint configuration, as well as on the prediction of a multi-bolt panel’s response.
32
OIWA, Takaaki, Takumi OHTA, and Satoshi OHKUBO. "Stiffness Improvement of Bolted Joint. Uniformization of Contact Pressure Distribution." Journal of the Japan Society for Precision Engineering 65, no. 4 (1999): 537–41. http://dx.doi.org/10.2493/jjspe.65.537.
Full text
33
YAMAMOTO, Hiroshi, Ying ZHENG, and Tomohiro NUMAZAKI. "Equivalent Stiffness of Bolted Joint Layer of a Spindle Rotor." Transactions of the Japan Society of Mechanical Engineers Series C 74, no. 743 (2008): 1702–9. http://dx.doi.org/10.1299/kikaic.74.1702.
Full text
34
Haidar, Nawras, Salwan Obeed, and Mohamed Jawad. "Mathematical representation of bolted-joint stiffness: A new suggested model." Journal of Mechanical Science and Technology 25, no. 11 (November 2011): 2827–34. http://dx.doi.org/10.1007/s12206-011-0725-0.
Full text
35
Musto, Joseph C., and Nicholas R. Konkle. "Computation of Member Stiffness in the Design of Bolted Joints." Journal of Mechanical Design 128, no. 6 (December 13, 2005): 1357–60. http://dx.doi.org/10.1115/1.2338578.
Full textAbstract:
In designing bolted connections in machinery applications, it is necessary to estimate the stiffness of the clamped members. The method of Wileman et al. (Wileman, J., Choudhury, M., and Green, I., 1991, ASME J. of Mech. Des., 113, pp. 432–437) has become a standard approach to estimating the member stiffness. In this method, finite element studies are used to estimate the stiffness of the clamped members of a single material type. In this paper, the studies performed by Wileman et al. (Wileman, J., Choudhury, M., and Green, I., 1991, ASME J. of Mech. Des., 113, pp. 432–437) are extended to include the case where the clamped members are of different material types. Results for a steel/aluminum joint are presented in detail, and a generalized technique for estimating the member stiffness for any material combination is derived. The method developed in this brief is shown to provide accurate estimates of member stiffness over a range of aspect ratios and joint compositions.
36
SHEHA, GABER. "A DESIGN ALGORITHM TO CALCULATE THE STATIC STIFFNESS OF' NUM-BOLTED JOINT. Part. I Joint Stiffness Analysis." International Conference on Applied Mechanics and Mechanical Engineering 2, no. 2 (May 1, 1986): 165–77. http://dx.doi.org/10.21608/amme.1986.57005.
Full text
37
Guchinskiy, Ruslan. "CALCULATION OF CONTROLLED TIGHTENING EFFORT IN GROUP BOLTED JOINT." Bulletin of Bryansk state technical university 2020, no. 6 (May 30, 2020): 12–21. http://dx.doi.org/10.30987/1999-8775-2020-6-12-21.
Full textAbstract:
The optimum value choice of a tightening effort is significant for assurance of a reliable operation of a group bolted joint. A work goal consists in the calculation and comparison of essential conditions of tightening efforts for a bolted joint of a bracket and a plate with analytical and numerical methods. For the first time it is obtained that the use of tightening factors recommended in literature by the condition of joint density may fail to ensure its non-disclosure. It is shown that a basic load factor for a bolt of a group joint depends not only upon bolt and flanges yielding, but upon loading and geometrical parameters of a joint. Basic loading factors obtained through a finite element method for a group bolted joint proved to be below ones defined analytically. The use of the procedure for bolt calculations on the basis of the assurance of joint complete non-disclosure results in increased values of tightening efforts caused by non-uniformity of contact stress distribution in flanges because of tightening. There is specified a field of application of the calculation procedure on joint non-disclosure – group joints with high stiffness flanges. At preliminary estimate the efforts for tightening a standard group joint a procedure of joint non-disclosure with the increased tightening factor and a condition of shift absence is recommended for use. To obtain a reliable estimate of the required tightening effort after its preliminary selection it is recommended to check up operation conditions of a group bolted joint with the aid of the calculation through the finite element method.
38
Liao, Xin, Jian Run Zhang, and Dong Lu. "Non-Linear Analysis and Modeling of the Structure with Bolted Joints." Key Engineering Materials 656-657 (July 2015): 694–99. http://dx.doi.org/10.4028/www.scientific.net/kem.656-657.694.
Full textAbstract:
In this study, a non-linear finite element model for a simplified single-bolted joint structure model is built. Static analysis on the structure under different shear force and pretension effect is done, and the non-linear contact behavior is analyzed. Through comparing datum, it is found that interface area of each bolted joint region can be described an annular region around bolt hole, whose outer radius has increased by 85% compared with radius of bolt hole. Also, the frequency responses of the multi-bolted joint structure under sinusoidal excitation are investigated. Simulation results show that the resonance regions basically remain unchanged in different pretension effect and the largest amplitude will increase with the increasing preloads. Finally, the vibration experiments are conducted. Interface nonlinear affect dynamic stiffness considerably. The test results illustrate that dynamic behaviors of bolted joint agree with the simulation results and the proposed non-linear contact model was reasonable.
39
Chen, Shiming, Junming Jiang, and Liangjiu Jia. "Numerical study on the performance of beam-to-concrete-filled steel tube column joint with adapter-bracket." Advances in Structural Engineering 21, no. 10 (December 27, 2017): 1542–52. http://dx.doi.org/10.1177/1369433217746345.
Full textAbstract:
An innovative beam-to-column composite joint with adapter-bracket was proposed and its behavior was investigated through finite element analysis. The special adapter-bracket is to facilitate the assembly of the steel box beam and the concrete-filled steel tube column through high-strength blind bolts. In the adapter-bracket, two endplates are welded to the beam and bolted to the column, respectively. First, two finite element models of the bolted extended endplate joint were developed in ABAQUS and validated by available experimental results. Then, based on modified models, parametric analyses were conducted to evaluate the novel joint performance, in terms of the initial stiffness, rotation capacity, moment capacity, failure mode, and joint classification. The variables included flange thickness, endplate thickness, and bolt size. Results demonstrated that the joint behavior was significantly affected by the flange thickness, the endplate-A thickness, and bolt size while slightly influenced by the endplate-B thickness. Additionally, these joints had favorable rotation and moment capacity.
40
Wang, Jing Feng, Xin Yi Chen, and Lin Hai Han. "Structural Behaviour of Blind Bolted Connection to Concrete-Filled Steel Tubular Columns." Advanced Materials Research 163-167 (December 2010): 591–95. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.591.
Full textAbstract:
This paper studies structural behaviour of the blind bolted connections to concrete-filled steel tubular columns by a serial of experimental programs, which conducted involving eight sub-assemblages of cruciform beam-to-column joints subjected to monotonic loading and cyclic loading. The moment-rotation hysteretic relationships and failure models of the end plate connections have been measured and analyzed. A simplified analysis model for the blind bolted connections is proposed based on the component method. It is concluded that the blind bolted end plate connection has reasonable strength and stiffness, whilst the rotation capacity of the connection satisfies the ductility requirements for earthquake-resistance in most aseismic regions. This typed joint has excellent seismic performance, so it can be used in the moment-resisting composite frame.
41
Wang, Fei, Jiang Li, Yu-qi Li, and Zhong Luo. "The investigation of vibration characteristics on the bolted disk–drum joints structure." Advances in Mechanical Engineering 11, no. 3 (March 2019): 168781401983147. http://dx.doi.org/10.1177/1687814019831477.
Full textAbstract:
In a bolted disk–drum joints structure, assembly parameters, such as the number and pretightening force of the tightening bolts, will affect the vibration characteristics of the structure. In this article, the influences are discussed. First, the influences of contact and structural stiffness on the natural characteristics of the joint structure are analyzed theoretically. Considering the micro-contact between the contacting surfaces of the bolts’ connected structure, the stress diffusion between the bolt head and the disk is investigated. Then, the relationship between the tightening torque and contact stiffness, as well as the relationship between the number of tightening bolts and structural stiffness, is established. Furthermore, the relationship between assembly parameters and the natural frequencies is obtained. Hence, the regularity of the influence on the structural natural frequencies can be summarized as a consequence. The results of experiment showed that the minimum error between theoretical calculation and experimental data was 1.5%, which provides a reliable analysis tool for the investigation of vibration characteristics on the bolted disk–drum joints structure.
42
Pan, Jian Rong, Zhan Wang, Lin Qiang Zheng, and Zheng Ting Yang. "Finite Element Analysis of Beam-Column Connection with Cantilever Beam Splicing." Advanced Materials Research 838-841 (November 2013): 540–44. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.540.
Full textAbstract:
Beam-column connection with cantilever beam bolted-splicing is also known as the joint of column-tree moment-resisting frame. The study is still relatively small for the semi-rigid behavior and rotational stiffness of the joint. This paper deal with four specimens of the joints with cantilever beam splicing and four specimens of the welded joints by using three dimensional finite element model analysis. The strain, stress, yield and ultimate loads, yield and ultimate deformations had been compared between the joint with cantilever beam splicing and the welded joint. The analysis results show that, when the splicing area of the joint with cantilever beam splicing was designed more strongly, the stress distribution, the load-displacement curves in elastic working stage, and the initial rotational stiffness are good agreement between the joint with cantilever beam splicing and the welded joint. The hysteresis curves of the joint with cantilever beam splicing were inverse S-shaped, indicating that there was greater slipping deformation because of bolt splicing. The welded joint had no slipping phenomenon.
43
Wang, Jing Feng, Xin Yi Chen, and He Tao Hou. "Experimental Study of Blind Bolted Joints to Concrete-Filled Thin-Walled Steel Tubular Columns under Cyclic Loading." Applied Mechanics and Materials 166-169 (May 2012): 78–82. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.78.
Full textAbstract:
This paper discusses results of experiments on blind bolted end plate joints to concrete-filled thin-walled steel tubular (CFTST) columns. Four exterior joints to CFTST columns subjected to cyclic loadings. A feature of this novel joint is the use of the blind bolts and extensions to these bolts into the concrete-filled square steel tubular column. Failure modes, moment-rotation hysteretic curves and energy consumption of the connections were analyzed. Further, the connection rigidity and ductility were also elevated by present specifications. The test results showed that the end plate type and the steel tube thickness affect the seismic behaviour of the typed blind bolted end plate joints. The proposed joint has reasonable strength, stiffness and ductility by taking reasonable end plate type, steel tube thickness and blind bolt anchorage; its ultimate connection rotation satisfies the ductility design requirements, and could be reliably and safety used in low-layer or multi-layer composite frames.
44
Unterweger, Harald, Markus Kettler, and Paul Zauchner. "Bolted angle members in compression –new design model including joint stiffness." ce/papers 4, no. 2-4 (September 2021): 2191–98. http://dx.doi.org/10.1002/cepa.1538.
Full text
45
Kettler, Markus, Harald Unterweger, and Paul Zauchner. "Design model for bolted angle members in compression including joint stiffness." Journal of Constructional Steel Research 184 (September 2021): 106778. http://dx.doi.org/10.1016/j.jcsr.2021.106778.
Full text
46
Xu, Jing, Jinhui Dong, Hongnan Li, Chunwei Zhang, and Siu Chun Ho. "Looseness Monitoring of Bolted Spherical Joint Connection Using Electro-Mechanical Impedance Technique and BP Neural Networks." Sensors 19, no. 8 (April 22, 2019): 1906. http://dx.doi.org/10.3390/s19081906.
Full textAbstract:
The bolted spherical joint (BSJ) has wide applications in various space grid structures. The bar and the bolted sphere are connected by the high-strength bolt inside the joint. High-strength bolt is invisible outside the joint, which causes the difficulty in monitoring the bolt looseness. Moreover, the bolt looseness leads to the reduction of the local stiffness and bearing capacity for the structure. In this regard, this study used the electro-mechanical impedance (EMI) technique and back propagation neural networks (BPNNs) to monitor the bolt looseness inside the BSJ. Therefore, a space grid specimen having bolted spherical joints and tubular bars was considered for experimental evaluation. Different torques levels were applied on the sleeve to represent different looseness degrees of joint connection. As the torque levels increased, the looseness degrees of joint connection increased correspondingly. The lead zirconate titanate (PZT) patch was used and integrated with the tubular bar due to its strong piezoelectric effect. The root-mean-square deviation (RMSD) of the conductance signatures for the PZT patch were used as the looseness-monitoring indexes. Taking RMSD values of sub-frequency bands and the looseness degrees as inputs and outputs respectively, the BPNNs were trained and tested in twenty repeated experiments. The experimental results show that the formation of the bolt looseness can be detected according to the changes of looseness-monitoring indexes, and the degree of bolt looseness by the trained BPNNs. Overall, this research demonstrates that the proposed structural health monitoring (SHM) technique is feasible for monitoring the looseness of bolted spherical connection in space grid structures.
47
Zhuang, Fujian, and Puhui Chen. "Effects of missing fasteners on the mechanical behavior of double-lap, multi-row composite bolted joints." Journal of Composite Materials 52, no. 28 (May 2, 2018): 3919–33. http://dx.doi.org/10.1177/0021998318771464.
Full textAbstract:
This paper presents a numerical investigation into the effects of missing fasteners on the mechanical characteristics of double-lap, multi-row composite bolted joints. A highly efficient explicit finite element model, which was validated effective and accurate by experiments, was developed and employed to conduct the virtual tests. Single-column and multi-column joints with various positions of missing fastener were considered. It is shown that the removal of fasteners can reduce the joint stiffness significantly, especially in joints with fewer columns or missing fasteners in the outside rows. The removal of fasteners can also cause considerable reductions in both the initial significant failure loads and ultimate loads of multi-column joints, while in single-column joints only the initial significant failure loads are influenced. Considering the load distribution, it is suggested that bolts in the same column as or in the adjacent column to the missing fastener experience a notable growth in load. Meanwhile, if a bolt bears more loads in the pristine joint, the larger changes in stiffness, ultimate strength, and load distribution may be obtained when it is lost.
48
Caputo, Francesco, Giuseppe Lamanna, and Alessandro Soprano. "Effects of Tolerances on the Structural Behavior of a Bolted Hybrid Joint." Key Engineering Materials 488-489 (September 2011): 565–68. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.565.
Full textAbstract:
In this work, results from a study on bolted joints made of unidirectional, quasi isotropic Carbon Fiber Reinforced Polymer (CFRP) composites, subjected to tensile loads, are reported. CFRP composite materials are widely used in the mechanical industry, such as that of aerospace, where requirements of weight reduction and structural high performances are very compelling. Composite materials generally present a high resistance to fatigue and corrosion; however, the presence of joints produces the major problems and a poor design of joints leads to a drastic reduction of the reliability of structures made of these materials. A hybrid bolted joint involving a metal plate, made of aluminum alloy, and a CFRP composite plate has been considered; the plates are held together by a titanium bolt. Experimental results from literature are compared with those obtained through a numerical analysis developed with Abaqus code. Once the CFRP composite has been analyzed and the numerical model validated through numerical-experimental correlations, other possible configurations have been numerically analyzed in order to ensure the highest strength of the examined hybrid joint. Afterwards the effects of bolt-hole clearance on the stiffness and strength of the same joint have been investigated.
49
Yu, Zeliang, Pu Xue, and Yue Chen. "Composite Single-Bolted Joint Simulation for Dynamic Strength Prediction." Proceedings 2, no. 8 (July 2, 2018): 512. http://dx.doi.org/10.3390/icem18-05424.
Full textAbstract:
Composite material has been widely used in various fields for its high specific strength and high specific stiffness, so the connectors applicable to composite structures capture many researchers’ attention. With the advantages of higher carrying capacity and repetitive assembling and disassembling, bolted joint becomes one of the most popular connectors in engineering practice. Cutting off the fiber and causing stress concentration are more serious to composite than metal, so it is necessary to predict the strength of the composite joints. Most investigations focus on the response under quasi-static loading, while dynamic effects should be in consideration in increasing impact conditions. The dynamic mechanical properties of composite joint may have a significant impact on the structural deformation and damage modes. For this purpose, this paper conducts dynamic composite single-bolted joint simulations in ABAQUS/Explicit, which used for predicting dynamic strength of the composite joint. T800/X850 laminates were tested to investigate their dynamic properties in our lab. Then the three-dimension progression damage model was established, while the dynamic constitutive model, damage initial criteria and damage evolution law of composite materials were coded in VUMAT of the finite element software ABAQUS/Explicit. The model was validated by quasi-static experiments of composite joint. The simulation results indicate that the yield strength and ultimate strength of the single-bolted composite joint are obviously increasing when consider the strain rate effect and dynamic loading. And the load-displacement curves show significant difference in damage stage. The main damages are sub-layer buckling and fiber breakage caused by extrusion.
50
Nassar, Sayed A., and Payam H. Matin. "Clamp Load Loss due to Fastener Elongation Beyond its Elastic Limit." Journal of Pressure Vessel Technology 128, no. 3 (August 5, 2005): 379–87. http://dx.doi.org/10.1115/1.2217971.
Full textAbstract:
The amount of clamp load due to an externally applied separating force is determined for a boiled assembly in which the fastener is elongated past its proportional limit, while the clamped joint remained within its elastic range. After the initial tightening of the fastener, the joint is subsequently subjected to a tensile separating force, which further increases the fastener tensile stress into the nonlinear range. Such separating force will simultaneously reduce the clamping force in the bolted joint. Upon the removal of the separating service load, the bolted joint system reaches a new equilibrium point between the fastener tension and the joint clamping force. At the new equilibrium point, the fastener tension is reduced from its value at initial assembly, due to the plastic elongation of the fastener. The reduction in fastener tension translates into a partial—yet permanent—loss of the clamping load that may lead to joint leakage, loosening, or fatigue failure. A nonlinear model is established in order to describe the fastener behavior past the proportional limit of its material, and to determine the clamp load loss due to the permanent set in the fastener after the separating force has been removed. Two fastener materials with significantly different rates of strain hardening are used for modeling the behavior of the bolted joint system. The effect of three nondimensional variables on the amount of clamp load loss is investigated. The first variable is the stiffness ratio of the joint and the fastener. The second is the ratio of initial fastener tension to the fastener elastic limit, and the third variable is the ratio of the separating force to the force that causes joint separation to start. Analytical results are presented for a range of stiffness ratios that simulates both soft and hard joint applications. Experimental verification of the analytical results is presented.