Papers by Keyword: Fastener

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Authors: Jong Eun Ha
Abstract: In this paper, we deal with robust detection of defects that can occur on fastener heads peripheral side. In machine vision, the first necessary step is design good illumination system that can give image with good contrast between good and bad samples. In our case, it is difficult to devise such a god illumination system. First, we find the outer boundary of fastener head using binarization, connected component analysis and checking local distribution of intensity. Then four control points on outer boundary is chosen to ease finding the inner boundary of fastener head using polygon approximation and line fitting. Finally, decision can be done using two detected boundary points of fastener head.
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: Mariusz Skóra, Stanislaw Weglarczyk, Jan Kusiak, Maciej Pietrzyk
Abstract: Computer aided design of the manufacturing technology for the fasteners is presented the paper. The particular objectives of the work were twofold. The first objective is evaluation of applicability of various materials for fasteners. Analysis of different technological variants is the second objective of the research. In the material part, bainitic steels are considered as an alternative for the commonly used carbon-manganese steels. This is a continuation of [1,2]. Possibility of elimination of the heat treatment was evaluated. Main features of the new generation of bainitic steels are discussed briefly in the paper. Rheological models for all steels investigated in the project were developed. The models were implemented into the finite element code for simulations of drawing and multi stage forging. Simulations of various variants of manufacturing chain were performed and the best alternative was selected. Criteria for the selection composed dimensional accuracy and tool life. Industrial trials were performed for the selected cycle and the efficiency of this cycle was evaluated. Finally, the optimization task was formulated. However, solution of the optimization problem is costly at this stage and improvement of the efficiency of the formulation will be the objective of further research. References 1. Kuziak R., Skóra M., Węglarczyk S., Paćko M., Pietrzyk M., Computer aided design of the manufacturing chain for fasteners, Computer Methods in Materials Science, 11, 2011, 243-250. 2. Kuziak R., Pidvysots’kyy V., Węglarczyk S., Pietrzyk M., Bainitic steels as alternative for conventional carbon-manganese steels in manufacturing of fasteners - simulation of production chain, Computer Methods in Materials Science, 11, 2011, 443 – 462.
Authors: Yu Zhen Ma, Xuan Sun, Yi Zhong Zheng
Abstract: Based on the working principle of the capacitive sensor, according to the requirements of deep hole diameter measuring, a capacitance probe sensor was designed, and then the design and type-selection of probe structure, cable inner structure to the capacitance probe sensor were done. At the same time, in order to overcome the measurement error caused by eccentricity, the capacitance sensor probe and inner hole of the corresponding fastener both are designed to a taper, taper positioning is relatively accurate positioning way. The design is to avoid the measurement position offset, and ensures the coaxality on the mechanical structure. The equipotential ring technology effectively overcomes the problem of edge effect of capacitance sensor, and makes the probe’s effective measurement electrode under the condition of limited long, can effectively guarantee the measure precision. By moving the capacitance probe in the hole to the different position, we will realize the deep hole diameter measurement in different cross section.
Authors: Xue Ren Zhang, Jing Xu Nie, G. Hou
Authors: M. K. Kathikeyan, R.K. Gupta, V. Anil Kumar, P. Ramkumar
Abstract: Medium carbon low alloy Ni-Cr-Mo steel is used in the fabrication of aerospace fasteners. It finds application in different heat treated conditions to meet the desired strength level. The alloy was realized through double melting route. Heat Treatment studies have been carried out by following different tempering temperatures to obtain varying strength levels ranging from 1200MPa to 1400MPa. Microstructural analysis has been carried out to find out reasons for variation in mechanical properties. Tempering cycle has been suggested to obtain fully tempered martensitic structure. This paper presents the different hardening and tempering cycles studied to obtain the desired strength level for the intended application.
Authors: P.S. Chauhan, C.M. Agrawal, R.K. Dwivedi
Abstract: The work in this paper presents the effect of material and blank dimension on the dimensions ofexternal rolled threads. This paper will be helpful for the auto industry, one of the largest fastenersmarkets, that typically consumes between 2800 to 3100 fasteners in the assembly of an average familyvehicle. Externally threaded fasteners comprise the bulk of fasteners used in these applications withover 90% of being produced by thread rolling. The thread rolling process is now widelyacknowledged as the fastest and most efficient method of producing accurate external threads, withsurface finish and mechanical properties. The typical production rates are around one piece persecond. In order to ensure a perfect thread rolling process, it is important for blank of work piece to beproperly pre-machined. The size of the blank is dependent on material, surface finish, type of threadsetc. This paper describes the effect of blank material and dimensions on nominal diameter of externalrolled threads. The work has been carried out at M/s Gayatri Auto Industries on Master ReciprocatingDies Thread Rolling Machine using HSS die. Mild Steel (C 15), EN-8 (C40), and EN-47 (SpringSteel) materials have been taken as blank material for the analysis to produce M8x1.25 6g threads.The result indicates that the variation on surface roughness, carbon percentage and dimension of blankaffects significantly the nominal diameter and PCD of threads. This paper is helpful for theprofessionals to determine the accurate dimension of thread rolling blank for desired threads tominimize rejections.
Authors: Qing Yun Zhao, Hong Huang, Qing Dong Xiao, Feng Lei Liu
Abstract: For 7050-T7451 plate with the thickness of 16mm, ∅6 hi-bolts were installed with 0.11mm interference by electromagnetic riveting. Split-sleeve cold expansion was employed with 4% expansion. Combine joining of 4% expansion+0.11mm interference was carried out. The effect of strengthening was estimated from microstructure, stress and fatigue life. The results show that the microstructures are the same before and after strengthened. Along the installing direction, materials flow locate near the exit. Residual compressive stresses generate by strengthening process and gradually increase by the process of interference bolted joining, split-sleeve cold expansion and combine joining, within some diameter in the exit. The fatigue lives N50 also gradually increase by the process of interference bolted joining, split-sleeve cold expansion and combine joining.
Authors: Xuan Dong Zheng, Chuan Zhi Geng, Teng Fei Qu
Abstract: In order to analyze the damping effect of high-elastic damping fastener on rail transit viaduct, Ls Dyna software was use to analyze rail and viaduct vertical vibration under different fastener damping constant. Fasteners with no damping constant and different damping constant are built in finite element model with rail transit viaduct, and the acceleration simulation results of them are compared to find damping effect on rail transit viaduct vibration transmission. The results indicate that the damping characteristic can attenuate vibration produced by wheel rail impact, however as the fastener damping constant are only parts of the whole damping system of the rail transit viaduct, the damping constant is not as better as its increment. The paper attempts to provide advice for employment of damping fastener in excessive vibration region of urban mass transit.
Authors: Rong Shi, Yue Lei He
Abstract: In this paper, rail fastening of shanghai metro line1,2,3,4, the species distribution from a variety of fasteners and fastening performance comparisons of the two main aspects of the investigation. To mastered the main content of the use of Shanghai Metro rail fastening. Analysis of the popular types fastener of Shanghai subway such as type WJ-2 fastener, type DTIII fastener, type DTIII-2 fastener, type II elastic fastener. Track fastener in the actual use of shock absorber characteristics of the process. Come to Shanghai Metro rail fastening design and selection of line with actual needs, Shanghai Metro rail fastening series featured a wide variety and distinctive. Also pointed out that lack of adjustable fasteners, fastener corrosion, fastener and the lack of vibration reduction and performance degradation caused by a wide range of management and maintenance of complex and emphasize on the use of investigation and analysis of search problems, tracking the course of the development, research the causes and improve the conservation measures to maintain rail fastening methods Keti the safe operation of the subway has a crucial role in.
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