Applied Mechanics and Materials Vol. 372

Abstract: This article mainly aims at analysis of local stress of lower chord of inverted triangle cargo boom of tower crane under the wheel pressure, taking the inverted triangle cargo boom of 70300 tower crane as the research object. Separately analyze the effects on the strength of the lower chord which is produced by the down flange, webs and changes of the car action point. Result from the analysis: When the distance between the two webs is too far and the car action points are closer to the webs, the force of lower chord is relatively good. Thickness of the down flange has bigger influence on the lower chord than the webs.

Abstract: Creep of rheocast 7075-T6 aluminum alloy produced by the Gas Induced Semi-Solid (GISS) process was investigated at temperature of 300 °C and stress range of 20-70 MPa and compared to that of wrought 7075-T651 aluminum alloy. The rheocast 7075-T6 alloy exhibited lower minimum creep rate and longer rupture time than the wrought 7075-T651 alloy. The total rupture strain of the rheocast alloy was shorter than that of the wrought one. According to the power law creep, the stress exponents, n of the rheocast 7075-T6 and the wrought 7075-T651 alloys were 5.9 and 7.9 respectively. Based on the determined n values, the creep deformation of both alloys was possibly controlled by the dislocation glide and climb-controlled mechanism.

Abstract: This study is focused on predicting the fatigue life expectancy of Girth gear-pinion assembly used in cement industries. Gear design and modeling was carried out using a CAD package and analysis was done using finite element analysis software, ANSYS. AISI 4135-low alloy steel material properties are considered and linear elastic finite element analysis and fatigue life analysis were carried out. The variable amplitude load is applied to simulate the real time loading of the gear-pinion assembly. Rainflow cycle counting algorithm and Minars linear damage rule is employed to predict the fatigue life. The critical stress and the corresponding deformation are discussed in the results. Finally the life expectancy of the girth gear and pinion assembly is estimated which would be useful for the periodical maintenance of the gear assembly.

Abstract: This paper deduced the force formula of the pin through applying load on the top beam.Using the Hertz formula calculating the mean stress and standard deviation of the pin.By using the stress-strength interference theory to calculate the reliability of the pin.

Abstract: The feasibility of using the transfer matrix method (TMM) to compute the free vibration characteristics of a system composed of continues and discrete elements vibrating in a plane is explored theoretically. In the approach to the problem, a general analytical method based on TMM is developed for the vibrations of two uniform Euler-Bernoulli beams coupled by a spring. The components of the transfer matrix are all functions of the systems natural frequency. The overall transfer equation only involves boundary state vectors, whereas the state vectors at all other connection points do not appear. The state vectors at the boundary are composed of displacements, rotation angles, bending moments and shear forces, which are partly known and partly unknown. Moreover, the overall transfer matrix is independent of the degrees of the freedom. A non-trivial solution of the final overall transfer equation requires the coefficient matrix to be singular. This paper reduces the zero search of its determinate to a minimization problem and demonstrates a simple, robust algorithm being much more efficient than direct enumeration. A numerical result is presented to demonstrate the proposal method.

Abstract: The concept of equivalent stiffness and equivalent negative stiffness is introduced in this paper, established the equivalent relationship between the force acting on the middle of variable cross-section column and the force acting on the top of constant cross-section column on boom tower crane lifting plane and slewing plane by the equivalent stiffness law and the equivalent negative stiffness method, The force on the middle of column is converted into the force on the top of column by the equivalent relationship.

Abstract: The article introduces the dynamic characteristics researches for dual derrick, they are wind load response analysis, the vibration characteristics analysis, seismic response analysis and wave load analysis. On the stability of the dual derrick check, the article recommends the nonlinear finite element method and the treatment of boundary conditions. Although these studies have a certain guiding significance for the practical engineering, but there is a relative lack of the study for the dual derrick on deep-water drilling rigs. To this end, the article points out research contents for the further study of dual derrick dynamic characteristics, proposes the idea that using the reliability analysis theory of large truss structure to research the reliability of the double derrick.

Abstract: Based on the theory of viscoelasticity, the Dynamic Shear Rheology test is used as study method. Study subjects are AH70 asphalt, SBS modified asphalt and MAC modified asphalt. Study objective is to analyze the effects of both high temperature and loading frequency on asphalt binder in asphalt mixture. Results from studies have revealed that: At high temperature and low loading frequency, the elasticity of asphalt binder decreases or low possibility of strain recovery, rutting resistance parameter decreases or the risk of rutting increases; At high temperature and high loading frequency, the viscosity of asphalt binder decreases or the strain speed of asphalt binder increases; At low temperature and high loading frequency, the fatigue resistance parameter increases, in other words there exists high fatigue cracking potential.

Abstract: This study demonstrates a designed pins-module tool and a precise reclamation system using a micro electroremoval process for sensing material of tin-doped indium oxide thin-films dissolved from a surface of polyethylene terephthalate of touch-panel. In the current experiment, a higher dissolution rate of the defective tin-doped indium oxide corresponds to high rotational speed of the cylinders tool with large flow rate of the electrolyte. A small diameter of the anode or a small diameter of the cathode combined with enough electric power, results in fast dissolution. The removal rate of tin-doped indium oxide thin-film is improved by decreasing the cylinders number. Importantly, the performance of a designed pins-module tool was found to be more effective in the micro electroremoval process. It requires only a short period of time to dissolve the nanostructured of tin-doped indium oxide easily and cleanly.

Abstract: So as to monitor and detect small shifts in the mean and variability of a manufacturing process, exponentially weighted moving average (EWMA) control charts are widely employed. Some of its extensions have been proposed to improve its performance. Among them, the Maximum generally weighted moving average (MaxGWMA) control chart is found as the superior. In the industry of coating pharmaceutical tablets, controlling the thickness of the coating layer containing active pharmaceutical ingredients is of great importance and in order to keep track on the coating quality, various methods using modern technologies have been proposed. However, decision support systems on the status of the coating process are not fully developed. Hence, in this study, MaxGWMA control chart was proposed to monitor the coating thickness of the tablets so that any small shift in the coating process can be quickly detected and further corrective actions can be implemented to make the process in control.