Applied Mechanics and Materials Vols. 84-85

Abstract: Removed due to plagiarism The original research was published as: SIMULATION OF ADVANCED UT PHASED ARRAY TECHNIQUES WITH MATRIX PROBES AND DYNAMIC SETTINGS FOR COMPLEX COMPONENT INSPECTIONS By: Chatillon, S.; Mahaut, S.; Dubois, P. Edited by: Thompson, DO; Chimenti, DE Conference: 35th Annual Review of Progress in Quantitative Nondestructive Evaluation Location: Univ Chicago, Chicago, IL Date: JUL 20-25, 2008 REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 28A AND 28B Book Series: AIP Conference Proceedings Volume: 1096 Pages: 864-871 Published: 2009

Abstract: With the development of the pioneering deployments in multi-hop wireless networks, although the relative research have not proven successful. The performance of routing and transport is often unstable due to contention induced packet losses, especially when the network is large and the offered load is high. A reliable wireless network architecture by using distributed control for large-scale multi-hop wireless networks has been present in this paper, The design objective is to optimize the control performance. This control performance is a complex function of the network parameters, such as throughput, packet delay and packet loss probabilities. The goal of optimizing the control performance imposes implicit tradeoffs on the wireless network design as opposed to the explicit tradeoffs typical in wireless data and voice applications. Our analysis suggests that our approach will deliver improved service to users while greatly reducing support effort and cost.

Abstract: In considering transmissibility of force and the output force of actuator, the transfer function was got between input excitations and out performance. Adopting different feedback control variable as velocity, force, full state etc, the H₂ optimal control was applied to double layer isolation system. By analyzing the amplitude-frequency characteristics of transfer function, comparing the advantages and disadvantages of various feedback control strategy, the best control method of H₂ is determined.

Abstract: Analyzed the commonly used method that machined large diameter hole bottom transition arc surface, it’ advantages and shortcoming. Through an example, we introduced the method of using the R parameter programming of SIEMENS840D numerical control system when milling cut large diameter transition arc surfaces. This method's application has the positive significance to reduce the programming and other non-productive work time, guaranteed processing quality, raised the machining efficiency, so we introduce this method and hope it is helpful to machining of similar parts.

Abstract: This paper presents artificial neural network techniques for predicting the compressive strength of Aerated Lightweight Aggregate Concrete (ALAC) based on the effects of the concrete mix parameters. The compressive strength of sixty different concretes with densities ranging from 551 to 1948 kg/m3 was used and trained. The primary mix design variables studied included amount of cement, water, coarse aggregate, fine aggregate, surfactant, the volume percentage of air in the matrix (A/M), and the volume percentage of matrix of the total mix (M/T). The training and testing results indicate that the model explains 0.984 and 0.979 of the variability in compressive strength for the single aggregate used in the study, respectively.

Abstract: In this paper, we took lathe as the research object, and established an active vibration control system model based on neural network AVC (Active Vibration Control) system, and the Matlab simulation results showed that the AVC system can reduce vibration effectively and improve the lathe’s accuracy.

Abstract: A high degree of integrity is the most remarkable feature that makes double-block ballastless track different from other ballastless track structure. Based on the beam/plate theory on elastic foundation, influences of several structural parameters (such as size of track slab and support layer, support stiffness of the subgrade, etc) on stress of the ballastless track system under the axle load of 300kN were studied in order to obtain further understanding of the mechanic performance of double-block ballastless track under the train load. Results show that: structure of double-layer combined structure should be adopted to decrease the stress of each layer of ballastless track; the width of support layer should be less than 3.6m; because the ratio of track slab stress to support layer stress is larger than the ratio of their strength, the width of track slab in the double-layer separated structure should be 280mm or less.

Abstract: After describing geometric characteristics of a PDC drill bit’s waterway surfaces, an approach for collision-free trajectory generation are proposed. The trajectory is planned by an iso-parametric method firstly, while the tool orientations are determined by visibility cones, which are the bounded regions between the opposite surfaces of neighboring blade wing pairs. Tool orientations are produced by calculations of critical points and interpolations between them. Furthermore, the criterion of whether tool orientations pass through the constraint surface and the linear interpolation formula of tool orientations are given. The research has created conditions for the success machining of PDC drill bits, and related machining enterprises of impellers and propellers will also be benefited.

Abstract: Ship-ship collision is a very complicated process, different collision parameters will lead to different results. Using ANSYS/LS-DYNA to build a model of ship-ship collision, it studies the side structure collision characteristics at different impact position and initial velocity. Based on the results of calculation, the collision force-displacement curves, energy absorbing-displacement curves, and the damage deformation of side structure are obtained. The simulation results indicate that changing the impact position and initial velocity will obtain the different form and degree deformation. In addition, the critical ship speed of ship shell ruptured is insured, which can offer the theoretical basis for maritime security management.

Abstract: Fascine objects can be applied in the process of emergency rescues in the Middle and Lower reaches of the Yellow River. Because fascine objects can improve the efficiency of rushing to deal with an emergency, adapt to changes in river bed conditions better, resist the erosion of water slide on riverbank and buttress and prevent the collapse of the embankment, they are applicable to rescuing grave dangerous situations such as river closure, advancing construction dams in waters, closing up levee breaches and so on. Based on the experimental study, the authors analyze the mechanical calculation results of fascine object’s underwater falling, and draw the relevant mechanical properties of fascine object’s underwater falling.