Papers by Keyword: Bend Strength

Abstract: Using a fiber laser welding head, crack-free WC-Co/Steel weld depositions are obtained with optimized welding parameters. The microstructure, composition, phase, structure, and bend strength are analyzed using optical metallography, scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and bend test. The influence of the microstructure and WC/matrix interfaces in the vicinity of joint failure at the cemented carbide side is discussed. It is evident that the deposit consists of austenite dendrites and interdendritic eutectic carbides. The austenite further transforms to martensite on-cooling. The flexural bend strength and yield strength of the joints attained 970 MPa and 876 MPa, respectively. Bend fracture occurs at the HAZ in the cemented carbide side of the joint, characterized with cleavage fracture and quasi-cleavage fracture. TEM and HRTEM image of WC/Co interfaces verified the W₂C and eta phase formation in the HAZ that contributed to the embrittlement.

Abstract: The working conditions of the ceramic cores are extremely harsh with the development of the preparation technology and improvement of the use conditions in the hollow blades, which brings forward high request for the preparation and properties of the ceramic cores. In this paper, silica ceramic powders were firstly coated by the silicon resin. The obtained composite powders were used to prepare the ceramic cores by the dry pressing method. And the phase compositions, microstructure and properties of the ceramic cores with the sintering temperatures were investigated. The results showed that the composite powders prepared by the coating showed good formability. The sintering temperature promoted the formation of the cristobalite. With the increase of the sintering temperature, the porosity of ceramic cores gradually decreased, the shrinkage rate and bulk-density increased. The prepared ceramic cores at 1250°C had highest bend strength of 19.25Mpa.

Abstract: In order to explore the dynamics performance of WN (Wildhaber-Novikov) gear transmission, according to the WN gear meshing transmission principle and the forced vibration theory with multi-mass and multi-degree of freedom, the nonlinear two degree of freedom forced vibration analysis model of WN gear pairs load meshing was established. Using vibration analysis and experiment, the meshing vibration behavior and tooth root bend strength of WN Gear were synthetically researched. The example calculation and the solution of the motion differential equations were completed by using numerical analysis method. The application foundation is improved for the dynamics design of WN gear transmission.

Abstract: Experiment with intensity level for the LC30 ceramsite concrete as the research object, changing the content of cement, GRT fiber, rubber powder by the orthogonal test to configure GRT fiber—rubberized haydite concrete samples, maintenance samples 7d and 28d in standard conditions and respectively testing their bend strength. Through the analysis of the test data, using multiple regression analysis established the GRT fiber—rubberized haydite concrete 7d and 28d bend strength regression formulas.By means of BP neural network theory combine MATLAB programme established GRT fiber—rubberized haydite concrete 7d and 28d bend strength neural network model.Finally using 3 groups new test data to compare the value of multiple regression equations and BP neural network’s predicted value.The results indicate that the multiple regression equations of 28d’s and 28d’s BP neural network model are availabled.But because of the water and cement which in the GRT fiber—rubberized haydite concrete can not hydration reaction sufficiently during the 7d’s,so the multiple regression equations of 7d’s is unavailabled.

Abstract: For the analysis and design of RC structures, there is a fundamental assumption that the strain in an embedded reinforcing bar is the same as that in the surrounding concrete. Therefore, bond forces must be developed on the interface between concrete and steel, such as to prevent significant slip from occurring at the interface. An end anchorage may be considered reliable if the bar is embedded in to concrete a prescribed distance known as the development length of the bar. If in the beam the actual extended length of a bar is equal to or greater than this required development length, no premature bond failure will occur. Research has indicated that the development length was influenced by tensile strength of concrete, surface and diameter of bar, cover distance, bar spacing, transverse reinforcement, and other factors. Current design methods in different countries’ Codes, attentions are directed toward providing adequate length of embedment, which will ensure development of the full strength of the bar.

Abstract: Based on normal elasticity equation, this paper has developed the calculation formula of face gear’s contact strength, bend strength and scuffing strength. This work put forward an analytical calculation method of face gear’s bend strength and constructed the analytical model. The result of bend strength of face gear was obtained by computer simulation. Based on the research, we designed and manufactured a suit of face gearbox. According to the tooth space trait, a method was represented to test bending stress of tooth by arrangement of sensing device in the tip end of the tooth of face gear. A test-bed has been set up with which the bending stress of tooth of face gear was carried out. The results showed that the maximal bending stress of test is similar to the simulation results by ANSYS.

Abstract: In order to fix on the inner connection of modification coefficient and bend strength, the static analysis of profile-shifted gear is made by applying Finite Element Method, then regression equation that revealed the relation between modification coefficient and bend strength is set up according to the Similarity Theory. Given bend stress of a standard gear, the bend stress of any profile-shifted gear with the same teeth can be calculated from the equation.

Abstract: Aluminum matrix composites containing of 10, 20 and 30 vol% TiB2 particles were compacted by underwater and direct shock wave consolidation methods. SEM and Optical Microscopic examination, hardness and bending strength measurements were used to characterize the samples. It is observed that there were different distributions of TiB2 particles in recovered compacts by each method. In the direct method, the distribution of TiB2 particles at the center and at the periphery of the sample was different whereas in the underwater method there was a uniform microstructure in the sample. The microhardness of the compacts increased with increasing TiB2 particle volume fraction in both methods. The results showed highest bending strength for the composite containing 20 vol% TiB2 particles.

Abstract: A recycling system was developed for the treatment of fiber-reinforced plastics (FRP) by superheated steam. The process was shown to be robust, coping with scrap of FRP and providing useful outputs in the form of recovered fibers and resin. In this study, glass FRP (GFRP) was decomposed at a chamber temperature above 370°C. Fibers were collected at purities of up to 80%. The tensile strength of recovered glass fibers was reduced by up to 50% although this depended on the temperature of treatment. Resin was separated from the gas stream by cooling it to liquefaction temperature of resin.

Abstract: This paper deals with fabrication and strength evaluation of biocompatible composites consisting of partially stabilized zirconia (PSZ) and pure titanium (Ti). The biocompatible composites of PSZ-Ti were fabricated by a hot pressing method of powder metallurgy. A volume ratio of PSZ and Ti was changed. Four-point bending tests and Vickers hardness tests of the PSZ-Ti composite were performed to determine the Young's modulus, bending strength, Vickers hardness and fracture toughness. These properties were characterized as a function of Ti volume fraction. The Young's modulus and Vickers hardness were higher than the prediction of the rule of mixture. The bending strength and fracture toughness were decreased with increasing Ti content. To discuss these results from a viewpoint of reaction products, the components of raw powders and sintered composites were investigated by X-ray diffraction analysis. It is concluded that oxide of titanium and other reaction products were created after sintering and they affected the mechanical performances of the composites.