Papers by Keyword: Three Point Bending Test

Abstract: High Pressure Die Casting (HPDC) is a foundry process particularly suitable for high production rates and applied in several industrial fields, but the amount of scrap, caused by defects or incomplete filling, is sometimes very high. Thus it is important to know which are the main causes of defect formation and their effects on microstructure and mechanical properties. This paper presents, within the European MUSIC project, the qualitative and quantitative results of a study conducted on AlSi9Cu3(Fe) alloy castings, referred to as Horse-shoe Reference Castings, specifically designed to generate different kinds of defects with different severity levels. The work focuses on the correlations obtained between the casting mechanical properties, their defect content in terms of porosity and oxide films and the process parameters adopted, mainly second phase plunger velocity and intensification pressure. The three point bending test was carried out on the four specimens obtained from the two appendixes of the casting. The fracture surfaces were studied by scanning electron microscopy (SEM) and optical microscopy (OM) highlighting that the defect content is clearly correlated to the mechanical properties and the process parameter settings.

Abstract: The high-speed P/M steel Vanadis 30 was austenitized at 1100 °C, quenched and tempered at various combinations of processing parameters. For one set of specimens, also sub-zero period, made at -196 °C/4 hours between quenching and tempering. The microstructure and mechanical properties have been investigated as a function of austenitizing time, parameters of sub-zero processing and tempering. There were used metallographic analysis, hardness measurement and three point bending test for the evaluation effect of heat treatment conditions to observed materials.

Abstract: The aim of the paper is to investigate the flexural behavior and property changes of concrete structures reinforced by steel fibers (SFRC) and to use the results for carrying capacity assessment of SFRC post-cracked slab on ground structure with subsoil interaction effect. Because the national codes cover neither design nor assessment of SFRC structures the investigation is generally based on the nonlinear fracture mechanics models to establish the stress-crack opening and load-crack mouth opening displacement relationship. Then the flexural tensile strength and residual flexural tensile strength of the post-cracked SFRC structure is determined with respect to subsoil interaction.

Abstract: The objective of this study is to improve the stiffness and control the failure mode of the pultruded glass fiber reinforced polymers (GFRP) deck members to meet the design requirements. In this study, the authors proposed that the GFRP member was affixed by another GFRP deck inside it to form a combined GFRP deck member; an epoxy mortar was filled into some of the hollow sections of the GFRP member; and the basalt/carbon fiber sheets was wrapped around the GFRP member in order to improve the ultimate strength and stiffness and also to change its original failure mode of the GFRP member. Eight GFRP deck specimens where investigated in the three-point bending test results for their ultimate strength, stiffness, and corresponding failure modes. Finally, the Euler beam theory was used to obtain the force-displacement relationships of the GFRP members and then to compare the experimental results.

Abstract: Objective: To clarify mechanical properties of 14 superelastic NiTi orthodontic wires by three-point bending tests. Materials and Methods: The three-point bending test was conducted with a midspan deflection rate of 5 mm/min under constant temperature range 36±1°C. Wires were deflected to 3.1 mm. All data were recorded during the unloading process at deflections 3, 2, 1 and 0.5 mm. to simulate the force a wire exerts as a tooth is moved into the dental arch from a position of malocclusion. Results: The delivered forces changed slightly when the deflection varied during loading and unloading. Sentalloy wire applied the lowest continuous force. Conclusions: Commercial wires may not behave similarly due to minor differences in the production process, and force varies greatly from brand to brand. NiTi wire brands must be selected carefully considering the severity of malocclusion and stage of orthodontic treatment.

Abstract: An attempt was taken to simulate the bending strength of diamond impregnated segments in three point bending tests by using a discrete element method (DEM). The influences of main bond matrix components (Fe and Cu), the porosity in the matrix, the coefficient of friction among the matrix particles, and the connection strength between abrasive particles and matrix particles on the bending strength were investigated through simulation. It is found that the bending strength increases with the proportion of Fe but decreases with the increase of porosity. An increase in both the friction coefficient of the matrix particles and the bonding strength between the diamond grains and metal matrix particles can also lead to the increase of bending strength.

Abstract: This article studies the effect of Uyghur sand therapy on rabbit femur bending mechanics. Methods: Papain was injected into the joint space of right knee of 20 male rabbits. The Paptain injected rabbits were divided into two different groups: sand therapy group and control group. The control group rabbits weren’t interfered in any way. The sand therapy group rabbits were given sand therapy for 30 minutes each day for 15 days. On the 16th day, the femur of each rabbit was taken as specimen. The specimen was given the tree-point bending test and the load-deflection curves were obtained. Then Finite Element Ansys method was used to analyze the stress cloud and the deformation cloud; Results:. Damage occurred in the position where the first maximum main stress was given; the form of damage was a brittle fracture. However, the position which corresponds to the maximum bending compressive stress has not been damaged. Finite Element Ansys analysis also showed a similar result. Conclusion: Sand therapy can improve femur bending strength and toughness.

Abstract: This paper presents a methodology to determine the durability of Quad Flat No-Lead (QFN) package. The QFN package is useful for improving the reliability of the package. A mechanical fatigue test namely three points bending cyclic test and signal analysis were proposed in this paper. The three points bending cyclic test method is a test assembly that supports a specimen on two anvils or rollers, and symmetrically loads the specimen on the opposite surface with an anvil or roller using micro-tester machine. For strain signal collection, a strain gauge was connected to the dynamic data acquisition system, and it was used for each tested QFN package for determining the response of the captured cyclic strain signal. It was found that the sinusoidal amplitude pattern of signal response has been obtained during the constant three points bending cyclic test. The obtained response signals were then analysed using the Power Spectral Density.

Abstract: This paper discusses some issues in micromechanical property of a newly developed Quad Flat No-lead (QFN) 3D stacked die package using three-point bending test approach. The relevant test methodologies were carried out in order to observe the flexural stress, strain, maximum load and deflection of the package. While performing the test, these QFN packages were positioned on the three points test bench, and the specific applied load was then applied and moved down until the package was clearly bent and broken. The related findings indicated that the maximum load was found to be at 251.52 N and the maximum deflection was obtained at 0.41 mm. The results were important for setting related testing parameters (load, stress and strain) before applying the three point cyclic bending test on the QFN stacked die package as the future work.

Abstract: In the present work, three-point bending tests have been performed on four commercially extruded 6xxx- and 7xxx alloys, one with a fibrous and one with a recrystallized grain-structure for each alloy class, with the bending axis orientated 0, 45 and 90° with respect to the extrusion direction. Microstructure and texture characterization as well as tensile testing of the same materials have been performed and correlated with the bending results. In general there is good agreement between the bending angle and the fracture strain for all alloys, with the highest values in the extrusion direction. However, there are no indications in the microstructure and texture that explain the large differences in bendability observed. Die lines and recrystallized layer on a fibrous alloy have been removed to investigate their effect on the bending behaviour. However, these effects also seem to be limited, and cannot explain the anisotropy effects observed in bending angles.