Papers by Keyword: Dynamic Parameters

Abstract: The dynamic parameters of long-span prestressed one and two-belt hanging roofs, for which the seismic wavelengths are commensurate with the dimensions of the structure in plan, are considered. Calculated expressions have been obtained to determine the dynamic parameters for symmetric and skew-symmetric oscillations depending on the length of seismic waves.To ensure the operational safety of unique buildings and structures, we studied the change in the structural properties of materials from unfavorable operating conditions, long-term, beyond design-basis static loads, high-intensity dynamic effects, compliance of the support contours and the possibility of local damage and from the failure of cables of the structures under study.

Abstract: This paper presents the dynamic characteristics and the proposed positioning performance of the system to them investigated experimentally. In this research, we developed the positioning system and we evaluated positioning accuracy. The developed system uses a servo motor for motion actuation. In this paper, we focused on studying the dependency of the positioning error – elementary errors – the position of the conducting element for the mechanism of the transformation of the rotation translation movement, representatively the mechanism screw – screwdriver and on emphasizing the practical consequences in the field of design, regulation and exploitation of the correct identification of all the initial errors in the structure of the mechanism, their character and the selection for an ultimate calculus of these which are of a real practical importance.

Abstract: A geometric and kinematic study between two structures of robots was performed, respectively a mechanical anthropomorphic structure, with bars and gears, with four degree of freedom, (dof), redundant (4R), which can avoid obstacles and a parallel manipulator with translation on three axes (3T). This 3T structural solution allows rapid and precise movements, which are important characteristics for machine building industry. All these features make the parallel manipulator to be an attractive alternative to the serial ones for high precision operations in a limited workspace.

Abstract: A geometric and kinematic study between two structures of robots was performed, respectively a mechanical anthropomorphic structure, with bars and gears, with four degree of freedom, (dof), redundant (4R), which can avoid obstacles and a parallel manipulator with translation on three axes (3T). This 3T structural solution allows rapid and precise movements, which are important characteristics for machine building industry. All these features make the parallel manipulator to be an attractive alternative to the serial ones for high precision operations in a limited workspace.

Abstract: The debris flow in Sewanzu gully was located in Heishui county of Sichuan province, which was 5.12 Wenchuan of sichuan earthquake severely disaster. It was large and very likely outbreak, which not only had posed a serious threat to the lives and properties of people, but also affected the reconstruction work going on smoothly. According to the basic features of the valley and the debris flow, the dynamic parameters,such as bulk density,flow rate,flow capacity and sediment flush-out were calculated.And then the hazard of the debris flow was evaluated quantitatively. The results could provide the basis for the governance and disaster prevention and mitigation of the debris flow gully.

Abstract: In this paper, we propose a method of calculation and optimization concerning the dynamic parameters including its normal stiffness and tangential stiffness. We establish a contact model and a dynamic model based on Hertz contact theory, deriving and calculating its normal stiffness and tangential stiffness. Based on the dynamic parameters obtained, we complete the finite element analysis (FEM) and make the modal experiment. verify the correctness and feasibility of the theory model and the FEM model through comparing the theoretical results with the experimental results. On this basis, we establish the dynamic parameters optimization model based on the ANSYS and MATLAB, and successfully obtain more accurate parameters which provide reliable data for the subsequent analysis.

Abstract: The seismic events in the last decades evidenced the vulnerability of the architectural heritage with respect to these phenomena. Therefore, timely provisional and permanent interventions are often required in post-seismic scenarios.In response to the call for more efficacious solutions, a great deal of interest has been given to glass fiber-reinforced polymers (GFRPs) composite. GFRP composites offer the advantage of high strength, low self-weight and durability.This research proposes some first evaluations on the dynamic behaviour of pultruded FRPs (Fiber Reinforced Polymers) strut and tie spatial structure for seismic protection of historical building heritage. The dynamic identification has been carried out using the ambient vibrations test to measure the mode of vibration, frequencies, displacements and damping ratios of the structures. The Operational Modal Analysis (OMA) has been carried out to identify the modal characteristics through poly-reference Least Square Complex Frequency-domain (pLSFC) estimator.Basing on the experimental results the dissipative capacity has been evaluated through the calculation of the behaviour factor q.The experimental dynamic parameters were used to calibrate a numerical finite element model employed under the hypothesis of kinematic equivalence to evaluate the q factor considering the elastic-brittle behaviour of FRP material. The dissipative capacity of structure was assigned to the global geometric configuration - frame with concentric diagonal bracings - through the strength hierarchy criteria locating the dissipative zones in the tensile diagonals. The analysis was carried out considering some typological variations to investigate the variability of the behaviour factor q.

Abstract: Stud welding plays an important role in fixing stud on car bodies. The quality of stud welding is seriously affect automotive security. During the stud welding process,stud welding machine by monitor welding current,welding voltage and welding time to determine the welding quality is good or bad,and uses the average parameter monitoring system,but there are many defects of welding quality relate to these instantaneous value of the parameter.Based on the above issues, designed a dynamic parameter detection system.through the real-time monitoring of dynamic parameter,it can more accurately detect the defects of welding quality.

Abstract: A geometric and kinematic study between two structures of robots was performed, respectively a mechanical anthropomorphic structure, with bars and gears, with four degree of freedom, (dof), redundant (4R), which canavoid obstacles and a parallel manipulator with translation on three axes (3T). This 3T structural solution allows rapid and precise movements, which are important characteristics for machine building industry. All these features make the parallel manipulator to be an attractive alternative to the serial ones for high precision operations in a limited workspace.

Abstract: The dynamic parameter model based on cellular automata was not taken into account interaction between pedestrian and environment,it resulted in quite different from that of in real life.So a new model was proposed by taking into account one of the interactions:repulsion.In the present work, evacuation involving repulsion problem was studied in the room with single exit.The expanded model based on dynamic parameter model is introduced by using the quantitative of repulsion.The model could be used to explore the different degree of panic through repulsion.The corresponding simulations of pedestrian evacuation with repulsion were carried out. It extends the constraint where the original model was applied. The improved model is more accordance with actual circumstance than the original dynamic parameters model.The improved model is not only expected to model evacuations in detail but also has high efficiency.