Advanced Materials Research Vol. 716

Abstract: The motion equations of a belt drive system incorporating frictions among pulley-pivot surfaces are established. In deriving the equations, theorem of the motion of the center of mass and differential equation of rotation of rigid body with a fixed axis are used. In a case study, the motion responses of a belt drive system with and without frictions among pulley-pivot surfaces are numerically simulated, respectively. The numerical results show that the frictions have significant influence on the motion of the belt drive system.

Abstract: There are six key points, such as steel truss column, hoisting frame, hoisting point, wire rope, wire rope connecting in the hoisting system which we construct the COMAC ministry of installed plant. This timely monitoring of several key points in the promotion process is to enhance the process controlled several indicators. For different key points used different monitoring methods for monitoring. The results showed that 6 monitoring method is reasonable, feasible. This method can provide some experiences to the construction and fabrication of the steel member of the project.

Abstract: B-mode ultrasonic images are often pervaded by the electronics noise and speckle artifact, which may make the interpretation of medical images difficult. In this paper, a legible method for ultrasonic image is constructed and it can be effective to suppress the noise and improve the images quality. Dynamic persistence technology based on temporal multi-frames is utilized to smooth the electronics noise and even lower speckle artifact. To reduce computing complexity, a sum table method and conjugate direction search approaches are applied to speed up estimation of motion vector. The guided image filter strategy is used to enhance the contrast and detail resolution for the processed image by persistence. Experimental results show that the proposed method is effective to smooth noise and enhance contrast of ultrasound image in vivo.

Abstract: By calculating the average distances between each anchor and the unknown nodes, the anchor filtering localization algorithm filtered the anchors with smaller average distances, and chose qualified anchors to improve localization precision, especially in the non-uniform sensor networks. Simulation results showed that the proposed AFDV-Hop algorithm achieved higher positioning accuracy either in uniform or non-uniform sensor networks. The improvement of positioning accuracy became more obvious as the non-uniformity of the nodes increased. The node positioning errors were reduced 20%~30% and 40%~50% by AFDV-Hop algorithm when the non-uniformities of the node distributions were 10%~20% and 30%~40% respectively.

Abstract: This paper presents a signal direction-of-arrival (DOA) estimation approach that possesses excellent performance in spatial and temporal correlated signals environments. Firstly, an algebraic solution of the null subspace is derived based on the Vandermonde structured steering vectors of uniform linear array when all the sources possess identical nonzero mean value, and then, the DOA estimation is obtained with a polynomial rooting method. The novel algorithm performs much better than the conventional algorithms in the situation that the sources are closely spaced or correlated, and simulations have verified the validity of the algorithm.

Abstract: In order to study the acoustic environment of a ship sonar platform, near-field acoustic characteristic of a compound structure with plates & a cylindrical shell (CSPCS) subjected to sound excitation is researched based on numerical simulation. Influence of frequency and sound incident angle on acoustic environment of CSPCS are studied. Study shows that the sound pressure field distribution of CSPCS is complicated. Sound pressure would be strengthened and weakened in different locations when sound pressure uniformly incident into CSPCS. Result shows that the sound pressure distribution is highly dependent on frequency and incident angle. Sound pressure field is more evenly distributed when sound wave frequency is low. Study also shows that the incident angle has considerable influence on the sound field distribution of strengthened and weakened area.

Abstract: Wear generated by the presence of frictiononknee joint contact surfaces can cause debris, which may lead to failure of the artificial knee joint. In this study, the effects of friction coefficients occur on the knee joint contact surfaces were examined by Finite Element (FE) method. The knee joint was modelled to represent the contact surfaces between femur, meniscus and tibia. The measured angle from 0° to 15° was applied to analyze contact stresses for normal walking condition. It was found that the position angle of the knee joint at 10°offers the maximum value of contact pressure and shear compared to other knee joint position angles.Therefore, further examination was carried out and the FE results showed thattheoptimal friction coefficient was within the range of 0.1 and 0.15.

Abstract: An unintended consequence is that some freedom in the introduction of innovative composite connections has been removed. The innovative aspects of this connection are in the use of partial restraint connections between steel beams and concrete-filled tube columns that utilize a combination of low-carbon steel and shape memory alloy components. A refined finite element model with sophisticated three dimensional solid elements was developed to conduct numerical experiments on the proposed joints to obtain the global behavior of the connection and develop simplified models. The paper argues that careful analytical studies can replace the requirement for physical testing present in current steel codes.

Abstract: In general, the process of extrusion can experience some problems, such as flow problems inside molds, and strain problems of products as a result of the cooling speed. We explore the flow problems and temperature problems inside the die of an extruding machine. An optimal model has been investigated experimentally with different types of die slots and lips. The area of stress concentration has been examined, and the life has been predicted by structural analysis and fatigue analysis. An experiment was carried out to verify the stabilization of the model by modal analysis and analyzing manufactured specimens.

Abstract: A reliability analysis on fire accident was made by using the L-R fuzzy number with the function of fuzzy fault tree theory. According to the statistics of running condition of field equipment and the fuzzy information provided by expert experience, the fault tree of fire accident in the cotton plant was built, and the fuzzy probability distribution of the explosion was gained. The structural importance of each basic event also was analyzed, and the most important factors which influence the system were established. It provides a new way and means for the safety analysis of the system and preventing fire accidents.