Papers by Keyword: Pre-Tightening Force

Abstract: High pressure gas cylinder thread joint is the weak link in high pressure gas cylinders, The cylinders in use and the operating process, the main causes of cylinder screw thread failure is the improper preload. In this paper, cylindrical high-pressure cylinders threaded,connection for example,according to the bottleneck and the bottlevalve for high pressure gas cylinder structure, material and mechanical characteristics, establishing 3D solid model of the high-pressure cylinders connected by using the finite element software ANSYS, 3D model is applied to high pressure cylinders, thread connection analysis.

Abstract: The covering pipe-ear is one of the important components of the overhead contact line system (OCS) for supporting loads. The finite element model of covering pipe-ear was established, as the pre-tightening force, wind load and ice load all have effect on it, the stress distribution law were simulated under 12 kinds of loading conditions. The results show that the pre-tightening force has remarkable influence on covering pipe-ear and 2500N pre-tightening force is appropriate for the aluminum alloy covering pipe-ear. It is useful for the catenary components static strength reliability design.

Abstract: This paper presents a modular designed autonomous bolt tightening shaft (BTS) system and an adaptive fuzzy backstepping control is designed for such a system. The BTS system is designed for the autonomous bolt tightening operation, which has a wide potential industry application. Due to its inherent nonlinear and uncertain properties, the BTS system is mathematically modeled as an uncertain strict feedback system. By employing adaptive backstepping and the approximation property of fuzzy logic system, the controller is designed step by step. Based on the Lyapunov stability theorem, all signals in the closed-loop system are proved to be bounded and tracking error converge to zero. Simulation results on the BTS system are provided to validate the effectiveness and performance of proposed autonomous system.

Abstract: In order to analysis modal characteristic of bearing with pre-tightening force on main spindle of numerical control lathe, this paper proposes a model of spindle modality analysis. This model is used to simulate the preloaded bearing shaft system modal, and the simulation results are verified by modal experiment. This paper takes 7005c as the research object to establish the equivalent-spring model based on the Hertz theory considering the pre-tightening force, whose focus is dealing with the contact between bearings rolling element and raceway. Then the model will be used to get the bearing stiffness for finite element simulation analysis. The shafting modal with preloaded bearing test platform is structured to get the shaft system modal parameters, which is compared with and verified the simulation analysis.

Abstract: High-speed press is pressure processing equipment that can form parts in high-speed operation conditions. In this paper, in order to improve machining accuracy, analyze ant-vibration performance using finite element method; analyze vibration effect of complete machine and combination machine with steel and cast iron material respectively. Observe vibration reduction in different screw pre-tightening force; Select the best body structure to do modal analysis. If the experimental results and the FEM results are the same, state the validity of the model. In dynamic characteristics simulation analysis, it’s more accurate when considering the effect of material and pre-tightening force.

Abstract: In this paper, the pre-tightening force on piezoelectric multi-dimensional force sensor is researched. Structure of multi-dimensional force sensor and piezoelectric quartz crystals are introduced and analyzed. The relationship between pre-tightening force and measuring range of force sensor is researched. Structural model of multi-dimensional force sensor is built and analyzed by FEM. Horizontal linearity in horizontal direction with different preloads is obtained. In order to verify FEM analysis, a reduced prototype of piezoelectric multi-dimensional force sensor is fabricated. Verification test is designed and made. The research will provide certain reference value for development of piezoelectric multi-dimensional force sensor.

Abstract: The simulation turntable is a high precision and semi-physical simulation installation. In order to meet high precision of turntable, the precision prescribed in all sets of axes of turntable is required during manufacturing process and assembly. Based on assembly process of three-axis simulation turntable, the detachable structure of U frame is designed. Components of the frame are formed by bolted joints. So the strength and stiffness of the U frame with bolted joints must meet initial design requirements, simple and reliable finite element simulation method of bolted joints is applied based on ANSYS software in the paper. The connection of screw threat pair is simulated by nonlinear elastic contact mode, and the preload to bolts is loaded though pretension element of ANSYS software. The numerical analysis is performed to confirm that the detachable structural U frame with bolted joints is satisfied with structural requirement and the strength of U frame is influenced by the pre-tightening force of bolt at the extent.

Abstract: The theoretical value of bolt pre-tightening torque coefficient is typically 0.2 on load boundary condition simulations.A set of measuring setup has been designed in present study.Through direct measurement and electric measurement,a torque coefficient of 0.15 has been measured.The effects of pre-tightening torque coefficient on bolt stress field are studied numerically.Results show that the coefficient has significant effect on bolt stress fields and relatively conservative results will be achieved if a theoretical value of 0.2 is chosen.Studies on stresses around hole-edge and comparisons with test values show that simulated results of and agree well with test data and the relative errors are no more than 15%.