Papers by Keyword: Deformation

Abstract: This study aimed to investigate how the heat treatment can influence the strain values ​​of an IF steel observing the different values ​​of the tensile, rupture and drain that were recorded during the tensile test. We analyzed five samples of the specimen (CP) using different combinations of heat treatments to enable evaluation of the behavior of material deformation by tensile test. The evaluation was performed using the deformation calculation of the ratio between the axial and radial deformations (anisotropy parameter). The results indicate how different types of thermal treatments influenced in their initial properties, generating materials with different characteristics.

Abstract: Deteriorate of prosthesis can be defined as the mechanical wear of the components moving on each other. It occur the change of the rise and the shape of the component. This load can be depend on the extent of the load, the material of the component, the thickness of the polyethylene layer, the smoothness of the machining, the hardness of the surface of the head component and also on the implantation method. A 26-28 mm head diameter can be optimal and the upper level of the allowable polyethylene wear per year is 0.1 mm. It is not easy to determinate the usability of the different types [.

Abstract: High-manganese austenitic steels are promising emerging automotive steels demonstrating high strength and ductility. The main deformation products observed in these steels are mechanical twins and ε-martensite, where the dominant deformation products vary quite strongly with stacking fault energy (SFE), which in turn is a very strong function of the alloy carbon content. In this research, a Fe-22Mn-0.6C sheet steel was decarburized to achieve a variety of through-thickness C gradients, thereby varying the dominant deformation products through the sheet thickness, with the overall objective of producing unique microstructures and mechanical properties. Microstructural analyses after interrupted tensile testing indicated that the amount of both mechanical twins and ε-martensite increased with increasing true strain, where the deformation products changed from mechanical twins at the higher-C core to ε-martensite at the lower-C surface. The spring-back properties of the C graded steels were also compared with reference to the effect of differential carbon concentration gradient.

Abstract: The brittle-to-ductile transition in fully pearlitic steels was investigated. The temperature dependence of the absorbed impact energy was measured with the blade speed of 0.0033 m/s. The absorbed energy per unit area increased with two steps as the test temperature increased: the first jump of around 10 kJm^-2 at 130 K and the second jump of around 22 kJm^-2 at 273 K. The twice jumps of the absorbed energy suggests a two-step brittle-to-ductile transition in fully pearlitic steels. SEM images of side surfaces exhibited that micro-cracks propagated through cementite lamellae at temperatures below only those of the second jump of the absorbed energy, suggesting that the deformability of cementite controls the second jump.

Abstract: A medium-carbon V-microalloyed steel (38MnSiVS5) with three different Al levels (0.006, 0.020, and 0.031 wt pct) was used to examine the interaction of V, Al, and N after hot deformation. A complete thermomechanical cycle was simulated in the laboratory using a Gleeble® 1500. Specimens were heated to a soaking temperature that varied from 1100 to 1250 °C for 5 or 45 min and control cooled to 1000 °C in 6 min, where they were compressed to 40 pct reduction at a strain rate of 1.0 s^-1. After compression, the specimens were control cooled to 500 °C at 0.25 °C·s^-1 and die quenched to room temperature. Additional specimens were processed without the compression step for comparison. The thermal and thermomechanically processed specimens were characterized by quantitative metallography and microhardness testing. The thermomechanically processed specimens with 0.006 wt pct Al maintained their hardness while reducing pearlite fraction by approximately 10 pct. The thermomechanical processed specimens with 0.020 and 0.031 wt pct Al showed a significant drop in microhardness and pearlite fractions, as compared to the thermal only processed specimens. The decrease in microhardness and pearlite fraction for the two higher-Al–containing alloys in both the thermal and thermomechanically processed specimens appears to follow the same linear trend, suggesting that AlN precipitation reduces the amount of N in solid solution, lowers the temperature at which V(C,N) precipitation occurs, and effectively reduces such strain-induced precipitation.

Abstract: In order to improve the repair quality and efficiency of automotive body collision damage, and ensure the safety and reliability of the automobile after repairing, the paper discusses the integral body deformation characteristics based on the analysis of automobile impact force. Aiming at structural damage of integral body, the paper makes body damage repair process, analyzes the main factors which affect the body fixed and measurement, and puts forward a method which uses a multi-point pulling and the computer 3D measurement system to repair the damage. Finally, the validity of the method is verified by the collision case. The results show that the method can effectively control the position deviation of the body structure not more than 3mm, it can also improve the repair quality of automotive collision and reduce reworking rates effectively.

Abstract: The impact of deformation and strain rate on the strain induced martensite (SIM) from 304M2 austenitic stainless steel was studied by using X-Ray diffraction, transmission electron microscopy. The results indicate that 304M2 is easy to have SIM because of the chemical component and microstructural characteristic. The amount of SIM has great relationship with the deformation and strain rate. It is found that the amount of SIM is reduced during high speed deformation. The obvious SIM can be observed with higher deformation, but the growth rate slows down. When the deformation rates are 8.3%, 55.0% and 67.3%, the contents of martensite are 6.55%, 15.35% and 16.21%, respectively. Compared with the slow stretching, the quick stretching leads to less martensite transformation. Moreover, the elongation of the specimens decreases. At the stable deformation stage, the temperature increases are 72.8 and 91.9℃, respectively, when the strain rates are 2×10^-2s^-1 and 5×10^-4s^-1. Therefore, the martensitic transformation and the deformation behavior of the austenitic stainless are affected by heating.

Abstract: To study the lining deformation characteristic of the cold region tunnel under the frost heaving force, a model test was designed, and the low temperature environment in the tunnel of model was made by refrigeration equipment, the groundwater inside the model was frozen, the lining structure deformation characteristic under the frost heaving force was analyzed. The results show that the lining was distorted under the frost heaving force, the lining strain of the tunnel crown and side wall was greatly, the maximum strain is 122μ, the lining strains of inverted arch and foot of wall was less, the minimum strain is 25μ.

Abstract: This paper introduces the analysis of three span continuous girder arch bridge under the action of live load whose middle span is concrete filled steel tube with Ansys. Through the analysis, the deformation and the maximum displacement can be got which may provide reliable reference for further study of the arch bridge.

Abstract: The degradation of laminated glass as a result of increased temperature has become one of the important problem of reconstructions and designs of new glass structures, for instance high-rise buildings that are exposed to the impacts of an intensive heating caused e. g. by sunshine. The temperatures during heating can reach very high values, commonly from 60 to 70 °C. The effect of heating was simulated using the thermal chamber where the glass panes with the size of 120 x 1100 mm were heated. The deformation course under the increase of temperature was continually monitored by a measuring unit. In total six types of foils joining particular layers of glass were examined. In this paper the experimentally gained results are compared with a numeric computer analysis and the particular kinds of interlayers are evaluated using the loss of shear interaction.