Papers by Keyword: Interference Fit

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Authors: Seung Jo Kim, Seung Hoon Paik, Kuk Hyun Ji, Tae Ho Yoon
Abstract: Laminated composite plates have lower interlaminar strength making it difficult to apply interference-fit rivet joining. In this paper, a three-dimensional finite element model has been developed in order to simulate the riveting process on composite plates. The finite element model is based on continuum elements and accounts for some important mechanisms involved in a whole riveting process. The stresses around the rivet hole and the deformed shapes of the rivet are presented together with the effects of the interference fit and the geometry of the washer when the rivet joints are subjected to the compressive load. The numerical results show the applicability of an interference-fit riveting in composite laminates.
Authors: Jae Soon Jang, Myoung Rae Cho, Won Ho Yang
Abstract: Cold expansion method and interference fit of fastener hole have been used for over 40 years by the aircraft industry to improve the fatigue life of structures because they induce compressive residual stresses around holes. Especially, interference fits are very widely applied in the industry, because of their simple manufacturing process. There have been only few studies on the difference in the effect between cold expansion method and interference fit. The purpose of this study is to compare the effect between cold expansion method and interference fit according to plate thickness. Furthermore, residual stress distribution according to real clamping force is also investigated.
Authors: Zeng Qiang Cao, Qing Hua Qin
Abstract: Interference-fit fasteners are used in large numbers throughout aircraft structures. Conventional installation methods are driving fasteners into aperture using pneumatic or hydraulic tooling, installation damage always occurs using these methods. This paper introduces a new method of driving interference-fit fastener using stress wave, reports on a comparison of driving quality between stress wave driving and hydraulic force driving. The experiments completed by authors indicate that stress-wave method can drive the fasteners with larger interference which conventional installation method can not implement; stress wave driving method provides high installation quality and repeatable results compared with the conventional driving method; and stress wave driving method is convenient to be used. The experiments prove that the protuberant material produced by stress wave method is less than that of conventional installation methods, this is advantaged to improve the fatigue strength of joint.
Authors: Ping Ma, Cheng Xiang Liao, M.L. Duan, J.K. Li, D.N. Li, B.L. Zhang
Abstract: Balance for high speed motorized spindle is most important, it will influence the dynamic behavior of the high speed machine tools. In this paper, the GD-IV high speed spindle is introduced. In order to improve its balance accuracy, the step interference fit is developed to connect the rotor and the shaft. The interference fitted assembly has been modeled theoretically, the analysis highlights that the tolerance of the interference fit consists of the static section and dynamic section, the static section is determined by the transmitting torque while the dynamic section is determined by the centrifugal force. The Calculation of interference fit for the GD-IV spindle shows that the dynamic section is about 4.5 times larger than the static. Furthermore, the three dimensional model of the step interference fit between the shaft and the rotor has also been built up with finite element method and the stress distribution on the mating surface has been calculated. The results show that the maximum stress occurring near the chamfer region of the internal surface of the rotor is up to 235 MPa lower than the permissible material stress 278 MPa, so that the design of the step interference fit is reliability and safety.
Authors: Guo Ping Wang, Hua Ling Chen, She Miao Qi, Lie Yu
Abstract: In this article, a metal diaphragm coupling is introduced. It is assembled by interference fit with the shafts. Based on two axial vibration styles, self-exited vibration and external exited vibration, of the coupling, physical model of the coupling is established. Stiffness and damping of the coupling are also solved and analyzed. Then, natural vibration of the coupling is researched and natural frequencies are acquired by analyzed and simulated method. Finally, axial vibration response of the coupling was presented based on a calculation example. Techniques are presented which permit the coupling designer to predictably modify the coupling and thereby make in-place retrofits should an axial resonance condition occur in the field.
Authors: Hong Yun Luo, Chun Jiang Liu, Kai Li
Abstract: In this study, a contacting model was investigated for interference fit shaft–hub system (rotor system) on rotational speed 30000 r/min by finite element method (FEM) which gives more complete and accurate results than the traditional method. 2-d and 3-d FEM contacting models were established first; then the stress distribution and contact state of rotor system which containing four interference fit couples were analyzed with the contacting FEM model system while the rotor system rotates on 30,000r/min. Finally, an optimal design of shrink range of the rotor system above was debated.
Authors: J.C. Xiao, S.H. Xiao, H. Wu
Abstract: The sintered neodymium-iron-boron (Nd-Fe-B) material is used in most of PM machines. The kind of PM materials has small tensile strength and cannot withstand large centrifugal force due to high rotational velocity. A nonmagnetic steel enclosure is needed to cover the PM material. The tensile stress of the PM can reduced by pre-pressure applied to the outer surface of the PM through shrink-fitting into the enclosure. Based on the elasticity theory and the elastic-plastic contact theory, in soft ANSYS it is feasibility to establish a finite element mechanical model of interference fit between the enclosure and motor rotor PM at high rotating speed. This paper simulates the effects of the temperature and rotating speed (centrifugal force) on the displacement and the contact pressure on the interference-fitting surfaces .By finite element non-linear contact model analysis, if setting up right fit clearance, this paper could ensure the security of the PM rotor under rotational velocity up to 300,000 r/min high and temperature up to 150°C.
Authors: Wei Hua Ni, Zheng Qiang Yao, Jun Tong Xi
Abstract: Based on static analysis, this paper investigates the effects of interference fit and axial preload on the performance of the low-speed angular contact ball bearing. The results show the bearing with heavy preload and large radial clearance has big contact angle and high axial stiffness. Besides, large interference could result in small contact angle but high axial stiffness. When the bearing has large interference the axial stiffness increases rapidly due to the effect of interference on the axial stiffness stronger than that of contact angle. And the stiffness formula in the paper could provide boundary conditions for the finite element analysis of spindle-bearing system.
Authors: Ai Hua Liao
Abstract: The impeller mounted onto the compressor shaft assembly via interference fit is one of the key components of a centrifugal compressor stage. A suitable fit tolerance needs to be considered in the structural design. A locomotive-type turbocharger compressor with 24 blades under combined centrifugal and interference-fit loading was considered in the numerical analysis. The FE parametric quadratic programming (PQP) method which was developed based on the parametric variational principle (PVP) was used for the analysis of stress distribution of 3D elastoplastic frictional contact of impeller-shaft sleeve-shaft. The solution of elastoplastic frictional contact problems belongs to the unspecified boundary problems where the interaction between two kinds of nonlinearities should occur. The effect of fit tolerance, rotational speed and the contact stress distribution on the contact stress was discussed in detail in the numerical computation. The study play a referenced role in deciding the proper fit tolerance and improving design and manufacturing technology of compressor impellers.
Authors: Peng Shang, Ying Zhan, Sheng Feng, Jian Zhou, Lie Yu
Abstract: High-speed couplings are the key parts of micro-turbomachinerys. They are assembled to shafts by interference fits, which can transfer large torque, are easy to produce and offer significant cost advantages. Considering of the influences of the torque, rotational speed and temperature variation, the interference fits between couplings and shafts have to be analyzed accurately in order to save the construction cost and reducing risk of invalidation accidents. In this paper, a model of the interference fit between a coupling and a shaft is developed to study the determine parameters of the interference value. Using the classic elastic plane stress theory, the exact solutions of the radial stresses, hoop stresses and radial displacements are obtained. Three determine parameters (the torque, angular velocity and temperature variation correction terms) are derived in order to calculate the interference value. Taking a high-speed microturbomachinery for example, the numerical results show that the interference value is dependent of the ratios of inner radius to outer radius of the coupling and shaft significantly. The torque, angular velocity and temperature variation correction terms are in the same order of magnitude. The present analytical solutions are expected to be useful in the structure design of the interference fit between a high-speed coupling and a shaft.
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