Advanced Materials Research Vols. 690-693

Abstract: Root systems, as the reinforced materials, are essential to increase slope stability and mitigate soil erosion. Polygonaceae family weeds are widespread in slope collapse watershed for its rapid growth and hardiness. Some growing around farmlands and ditches affect the farm crop yield. While others growing in slope collapse have medicinal value, revegetation, and root reinforcement effect. The plant height, fresh weight and expansion range of aboveground biomass and roots were measured to research the relationship between the aboveground biomass and the belowground biomass. The relationship between the aboveground biomass fresh weight and root system fresh weight was consistent with linear function. Single root was tested by digital display push-tension meter (SH-100) fixed in vertical electrical machine (SJY-500) to obtain the relationship between tensile force and root diameter. The relationship between tensile force and root diameter conformed to exponential decay function. At last, the relationship between root diameter classes and average tensile force of Polygonaceae family weeds was analyzed. The result showed that the diameters mainly ranged from 0 mm to 2 mm, 87.75% of the total, and the average tensile force increased with the diameter class. At the beginning, the shape of tensile force was a line, then a curved line during pulling, which deformation was nonlinear. It could provide a scientific basis for design of weeder in farmland, and greening, erosion control in slope collapse.

Abstract: The failure shaft for light hydrocarbon pump was analyzed through metallographica test. The fracture appearance was examined through 3-D stereoscopic digital camera and the scanning electron microscope (SEM). The results showed that the chemical composition of the shaft was fit to the requirement of structural steel. There was sulfide inclusion distributed among the white stripe phases. The figure of phases was striation, and the direction of striation was along the direction of the axis that was the machining direction when the shaft was fabricated. The fatigue fracture was the facture characteristic because there was fatigue striation on the fracture surface. The sulfide inclusion and segregation was the main reason of the fracture.

Abstract: Based on the deformations under the equivalent external forces are the same, a new element model of elastic perfectly-plastic and orthotropic solid bodies is presented, and the elastic perfectly-plastic and isotropic materials is a special subclass. Furthermore, the method for determining the displacements, the stresses and the strains of a body under the action of applied forces has been given. A new method for predicting the engineering elastic constants of a fiber-reinforced composite material is also presented. It can be found that the precision by using the new element method is good, and the limit analysis has the highest precision in all methods.

Abstract: Three-dimensional stresses are analyzed in the tubing working based on the theory of thick-walled cylinder, and the stress intensity factor expression is derived on longitudinal and circumferential extending cracks in the tubing. Tubing fatigue life is calculated according to given condition through the preparation of the corresponding program. Influence of initial crack length, change of the pressure and the tubing wall thickness on the fatigue life are discussed.

Abstract: Field kitchen units is used to guarantee the diet in field operations for troops, a set of field kitchen units includes 3 boxes and 1 tent for kitchen work, cooking staple and non-staple food for 150 people in 1 hour. The weight of units has to be reduced so as to guarantee its application in Tibetan plateau of 5000m as it can be loaded on the vehicle by 2-soldier moving laterally or 3-soldier lifting. Mechanics analysis is carried out in this paper for the structural of latest applied carbon fiber composite units, in an effort to ensure the box can bear the impact generated in the course of transportation and loading, software LS-DYNA is applied to make finite-element analysis to simulate drop simulation test, checking if the strength of box structure reaches the designed requirements.

Abstract: The longterm field investigations in the US showed that punchouts were the most important distress in continuously reinforced concrete pavement (CRCP) and often developed in the cluster cracking with the crack spacing of 0.3m-0.6m. But, it was not sure whether punchouts were the most important distress in CRCP in China, so this paper carried out field investigations on several CRC pavements in China. Results showed that punchouts were the most serious distress and often occurred in cluster crack regions. Furthermore, this paper analyzed the transverse crack spacing distribution. Results showed that the transverse cracks spacing distribution followed Weibull’s distribution.

Abstract: In this paper fractional order integral model is set up about quality factor. Complex rectangular and Chebyshev polynomial are utilized to approximate the fractional order integral equation. Moreover, plane wave is used to calculate quality factor-Q. The numerical results show that Chebyshev polynomial approximation is more suitable to describe integral modeling of quality factor.

Abstract: From the aspect of the fastest exit speed of the ball and through the collision model of mechanics, we analyzed the best hitting point which results in the fastest exit speed of the ball and the change of the best hitting point. Based on this model, we gave a very practical definition of the sweet spot, and we also found out the effect of the baseball bat’s material on the sweet spot. The distances from the best hitting point to the end of the baseball bat result from the three different materials, which are the bat’s original material, aluminum and the corked material. Through the sensitivity analysis, three parameters affecting the hitting position resulting in the ball’s fastest exit speed are the weight of the bat, the center of mass and the moment-of-inertia. In the process of the three parameters’ calculation, the infinitesimal method is used. As can be found out that the length of the sweet spot results from the corked and the aluminum are much longer than results from the original material. The longer the length of sweet spot, the possibility that the hitter hits the fast ball is higher. Also ball hit by the aluminum bat is faster than that hit by the bat made out of the original material. The above analysis can explain that why the aluminum bat and corked bat are prohibited by Major League Baseball

Abstract: The modern mechanical excavation machines have enough power for cutting hard rock. The bottle neck which limits the use of machines for hard rock excavation is cutting tool. To cut hard and abrasive rock, CSIRO has been developing Super Material Abrasive Resistant Tools (SMART*CUT). SMART*CUT technology replaces the tungsten carbide (WC) tip of conventional pick with thermally stable diamond composite (TSDC) and attaches the TSDC tip to steel tool body with CSIRO worldwide patented bonding technology. This paper compares its performance with conventional WC tipped tools by a series of hard rock cutting tests. The cutting and normal forces acting on the tools were measured during these tests. The tests shown that the cutting performance of SMART*CUT pick was significantly better than that of WC pick. The testing results indicate that TSDC can be applied as an effective cutting tool material for cutting hard and abrasive rocks.

Abstract: The matter-element model of mechanical properties of materials for grade-evaluating is established based on the matter-element theory and extension evaluation theory in the Extencis. Then the dependent function derived from extension set is used to calculate integrated correlation degree, after the Weight of each evaluation index is determined, then the grade of corresponding material will be obtained. take the metal materials for example, the results have proved that this kind of extension evaluation method applied is sure to be more scientific、normative, fair, and reasonable, which deserves to be populated and generalized.