Applied Mechanics and Materials Vols. 117-119

Abstract: The knee and ankle muscle strengths of excellent male 500 meters skating athletes were measured and analyzed by means of the CYBEX NORM isokinetic testing and rehabilitation system. The study provides scientific basis for the coaches understanding the practical muscle capacity in accordance with special event, and for the analysis on athletes’ practical training level, potentials and drawbacks of main special muscles. The results are as follows: there are distinct differences between the two groups in some muscles of knee and ankle. The muscle strength features of international skaters are better than national skaters’.

Abstract: Fish biological sounds reflect abundant information of its living state. It is important to systematically conduct research on the fish acoustic features. This paper designs program code based on Fast Fourier Transform (FFT) to deal with the sounds in frequency domain. By applying the program to analyze the sounds of piranha, oyster toadfish etc., the feature of main frequency is obtained and the sound features of different fishes are compared. This paper further designs the sound detection experiment about the acoustic spread distance; analyzes the sound decibel value varying trend according to the result. The different features among the fishes illustrate the sound difference. Acoustic spread detection experiment provides the fish behavior control feasible distance in the taming system design.

Abstract: Ground settlement, especially the ground surface settlement induced by subway tunneling is an important issue. However, there is no an agreed standard for controlling ground surface settlement during the subway construction at present. The control standard of ground surface settlement was studied using the methods of statistical analysis and numerical simulation based on the running tunnel in Beijing subway. According to the research results, a conclusion could be obtained that the ground surface settlement can be controlled within 40 mm using the general construction measures in Beijing subway running tunnel construction, and furthermore, the settlement of 40mm will not damage the existing nearby structures and utilities including neighboring buildings, bridges and pipelines, etc. So the control valve of 40 mm is rational, which can be adopted as the control standard of ground surface settlement induced by running tunnel construction in Beijing subway.

Abstract: In this paper, a kind of conical bottom-supported offshore wind turbine foundation was developed. The finite element model was built in SESAM and the structure was analyzed in operating condition and survival condition. The result shows that both the bearing platform and the conical bottom can satisfy the requirement of displacement and strength. The new kind of platform can be applied in shallow sea and offshore, easy to tow, and has low cost, which is helpful to offshore wind power exploitation.

Abstract: After a series of impactful predigestion,the paper established one elbow joint dynamic model in the sgittal plane when the humerus was not fixed. According to the results of the example, two conclusions were drawed: firstly, the joint reaction engendered when the humerus movable were far less than the situation of fixing;secondly, we suggested ,when upright position bend elbow strength training was making , desirable buckling shoulder angle position is at 10⁰~20⁰ .

Abstract: The knee and ankle muscle strength of excellent male skating athletes is measured and analyzed by Cybex isokinetic testing system. Based on the features of athletes’ muscles strength, the study aims to find if there are differences and shortages between long track and short track speed skating athletes and whether they can learn from each other in the training, then to make the further discussion on the event itself. The main conclusions are as follows: 1. In the index of maximum strength, the torque/BW features of knee and ankle of the short track athletes are more fit the law of skating event, while the long track athletes do good in low speed, but opposite in high speed. The long track skaters need to improve the strength in high speed. 2. In the index of flexor-extensor, both long and short-track are lower than the recommended values, especially the short track. The two groups need to improve the strength of flexor muscles and to keep balance and coordinate of knee muscles. 3. In the index of acceleration, the power values of long track skaters are higher than short track skater’s, except left extensor muscles. The left extensor muscles of long track skaters are lower than their right ones, and should improve the balance of both legs. The short track skaters need to improve the powers of left and right knees in all speeds.

Abstract: Abstract: The polydimethylsiloxane (PDMS) film was applied a tensile strain, next the following steps was should be done: fixing the tensile strain, sputtering the gold film on the surface of PDMS film, and then releasing the tensile strain, a large-scale area ripple structure was formed. The ripple dislocations, the cracks and the oriented surface cracks appeared simultaneously during the forming of the ripple structure. This study also discussed the wavelengths of ripple structures resulted from the amount of tensile strain (30%, 50%, 70%, 90% and 110%) and gold thickness (4Å and 10Å). The wavelengths of ripple structures decreased as the tensile strains increased and gold thickness decreased.

Abstract: The tests on the vortex-induced vibration (VIV) of the cylinders with different helical strakes were carried out in a uniform current. Both in-line and cross-flow responses were measured and a comprehensive analysis was made in order to understand the phenomenon of VIV mitigation by helical strake and find optimal design parameters, which are more effective for VIV mitigation, of helical strakes. The results show that the cross flow response of the cylinders with helical strakes could be reduced significantly and its in-line response may be enhanced severely. Therefore, much attention should be paid to the design of helical strake.

Abstract: The multi-joint measuring arm’s measurement accuracy is associated with the measuring pose configuration. As the feature of the multi-joints arm with the adjacent joint orthogonal design, the triangle-based representation of measuring arm configuration was derived. Then measuring arm pose configuration simplified representation was presented. Based on the simplified representation, a polynomial model of comprehensive error compensation was proposed, and the calibration algorithm was derived.Tests confirmed the effectiveness of the method, which can effectively improve the single-point measurement accuracy.

Abstract: Slab quality affects the quality of hot rolled sheet significantly. There were serious transverse corner cracks on continuous casting slab of 510L steel plate in Panzhihua Steel before. Based on this, some effective countermeasures are put forward, such as the optimization of ratio of heat flux on narrow side and broad side of casting slab and mold powder, as well as the stabilization of casting speed and working condition of caster. With these countermeasures, transverse corner cracks on continuous casting slab have been significantly reduced, and the lines and peeling defects on hot rolled sheet reduce from 30% to 0.