A magnetorheological (MR) damper is one of the most advanced devices used in a semiactive control system to mitigate unwanted vibration because the damping force can be controlled by changing the viscosity of the internal magnetorheological (MR) fluids. This study proposes a typical double coil MR damper where the damping force and dynamic range were derived from a quasistatic model based on the Bingham model of MR fluid. A finite element model was built to study the performance of this double coil MR damper by investigating seven different piston configurations, including the numbers and shapes of their chamfered ends. The objective function of an optimization problem was proposed and then an optimization procedure was constructed using the ANSYS parametric design language (APDL) to obtain the optimal damping performance of a double coil MR damper. Furthermore, experimental tests were also carried out, and the effects of the same direction and reverse direction of the currents on the damping forces were also analyzed. The relevant results of this analysis can easily be extended to the design of other types of MR dampers.

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Tower crane as the main equipment of building trades, the failure of Hoisting mechanism is particularly important for complete machine working performance and device safety. In this paper, the failure of tower crane hosting mechanism is analyzed, the failure mode of hoisting mechanism is researched, the failure probability of hoisting mechanism is built, the various factors in the work influence on the tower crane hoisting mechanism is analyzed, use coefficient modification method to correct influence factor of hoisting mechanism, according to the series system theory to calculate the failure probability of tower crane, Provide the basis for the whole risk assessment.

This paper deals with solution to building tower crane fleet wireless communication system. Feasibility of a system based on ZigBee module is analyzed. By researching transmitting mechanism of ZigBee module and analyzing interference factors during the transmission period,experiments are designed to test data transmission and anti-interference performance, on the condition of simulating on-site environment. Experiment results show that the wireless communication system based on ZigBee module is feasible and the data transmission is reliable.

In this subject, there were the Analysis Parametric Design Language (APDL) and optimization of the design process to be introduced. Based on APDL and optimization design module of ANSYS, the structure of suspension mechanism was optimized and the extraction of the maximum stress of the beam structure was realized according to the actual work of the large load temporarily installed suspended access equipment. The optimization of product structure was achieved and the utilization of materials was improved by the minimum structural quality of the suspension mechanism as the optimization objective. The study could provide reference for the similar products on design and development.