Papers by Keyword: Bolts

Abstract: The paper presents an experimental investigation of the influence of thread length and tightening torque of the M8 and M12 bolts on the vibration fixture response. To perform the tests electromagnetic vibration exciter with amplifier (LDS V8900), controller (M+P), single-axis control and measurement accelerometer (PCB), and calibrated dynamometric key (Hazet) were used. As vibration profile was used sinusoidal on a linear scale amplitude (g²) versus time (Hertz) according to the IEC 60068-2-6 standard. To investigate the length and diameter of the bolts aluminum 7075 T6 fixtures with dimensions of 40 mm ´ 40 mm width and different lengths were used as part of the samples. It was found that the investigated parameters have a major influence on the vibration fixture response.

Abstract: The paper sums up the results of a complex analysis, using metallographic, microfractograpic and other methods, with the aim of establishing the cause of fractures appearing in bolts of a terminal board. The analysis has shown unambiguously that the bolt failure was a synergic effect of inadequately performed heat treatment and hydrogenation that occurred in course of surface treatment via pickling and subsequent zinc plating.

Abstract: The concepts of structural safety embedded in recognised international standards for the fatigue design of bolted joints, such as VDI 2230 Part 1, are examined and challenged. This is done by means of theoretical investigation of the behaviour of bolted joints using non-linear finite element analysis. Potential differences between actual bolted joint parameters and behaviour, and implicit design assumptions, are reviewed and their effect on the structural safety of bolted joints in operating equipment examined. An approach to the fatigue design of bolted joints is presented which incorporates alternative concepts of structural safety and uses advanced CAE methods as part of the standard design process.

Abstract: Guide rails which take place in structure of elevator, are the important elements for safety of elevator systems. They have attached together end to end with the fishplates and bolts, and are anchored to wall with brackets. Connections between guide rails and brackets are provided by clips. To ensure the safe operation of elevators, the guide rails, fishplates, brackets, bolts, clips have enough strength against to loads and forces which affect these elements. In this study, shear tests are performed to examine mechanical properties of bolts and clips which are used guide rail anchor element. The results which are gained from stress calculations and experiments are compared and interpreted.

Abstract: The hot-dip galvanizing coating can promote the anti-corrosion performance of the bolts in outdoor steel structure engineering. But the anti-corrosion performance cannot match that of the steel due to the centrifugal process. In this paper, the anti-corrosion performance of four kinds of bolts obtained from different company was researched by the neutral salt spray test method. The results show that the anti-corrosion performance of the all four bolts was unsatisfactory. The reasons were studied through testing the thickness of the coating, coating uniformity, surface morphology and elemental composition. The results show that the causes are the lower thickness of the hot-dip coatings, too much defects on the surface of the coatings and the elemental composition impurity.

Abstract: The main focus of this study is to investigate the clip-angle connections are described the section based on ideal limit states. The connection components are designed in accordance with the 2001 AISC-LRFD Specifications and the 2005 AISC Seismic Provisions. In the suggested clip-angle connection, the structural beam can be connected to the column using six high-strength bolts. The slippage on the shear faying surface contributes to increasing energy dissipated capacity in the connection behavior. The design of the clip-angle connection should include these mechanical characteristics. Therefore, this study presents new design methodology that can be applied to bolted clip-angle connections. Besides, step-by-step procedures for design will be treated herein.

Abstract: This paper is mainly performed to investigate T-stub connection that is described on the basis of ideal strength limit states. The determination of T-stub based on the full plastic strength of the steel beam in accordance with 2005 AISC Seismic Provisions. The T-stub connections considered herein were performed to include the T-stub component of bolted moment connection frames. Therefore, the proposed T-stub models will be evaluated by comparing the required factored bar strength. T-stub components using ten high strength bolts with wider gages are demonstrated in this design. In addition, equations for connection design will be described in this paper. Finally, new design methodology is applied to T-stub connections suggested in this study.

Abstract: C/SiC substrates and M3 bolts were prepared by precursor infiltration and pyrolysis (PIP) process firstly, then the joints with four joining methods (2 φ3mm soft pins, S-A; 2 M3 bolts, S-B; 2 φ3mm soft pins plus 8 φ1mm soft pins, S-C; 2 M3 bolts plus 8 φ1mm soft pins, S-D) were assembled, finally several PIP cycles were continued to finish densification. The influences of different joining methods and PIP cycles (3 or 6) on the stripping properties of C/SiC joints were investigated, and the fracture modes were analyzed. The stripping loads of the joints adopting 6 PIP cycles are almost two to six times the values adopting 3 PIP cycles, and the corresponding fracture modes are pins or bolts rupture and pull-out, respectively. When adopting 3 PIP cycles, the bearing ability of the joints with bolts (S-B and S-D) is about 51% higher than that of joints with pins (S-A and S-C), but when adopting 6 PIP cycles, the values with pins (S-A and S-C) is about 67% higher than that with bolts (S-B and S-D). Besides, the introduction of φ1mm pins enhances the bearing ability of the joints with 3 and 6 PIP cycles about 45% and 14%, respectively.

Abstract: Conventional triaxial compression tests of coal specimens are carried out by MTS815 servo-controlled rock mechanical test system, and the strength and deformation characteristics of coal under different confining pressure are analyzed. On that basis, bolt supporting mechanism of surrounding rocks of roadways driving along next goaf is studied.