Bending Test

Avialable measures of the fracture energy GF obtained with the procedure proposed by RILEM TC-50 provide values that appear to change with sample size, calling into question whether GF can be considered as a material parameter. In a previous paper, possible sources of energy dissipation from the testing equipment and lateral supports were considered. In this paper new possible sources of energy dissipation in the sample, apart from the fracture crack itself, are considered. Such dissipation will take place inside the bulk of the most stressed regions of the specimen and, if it is not taken into account, higher values of GF will be recorded than that strictly due to surface fracture energy. When this constribution and the possible energy dissipation analysed in previous work are considered, they are not enough to account for the measured size effect. If GF is to be considered a material parameter, the evaluation of the results from the RILEM method should be analysed more carefully. In any case, the dissipated energy reported here represents a non-negligible amount of GF and should be taken into account when performing measurements. Les mesures de l'énergie de rupture GF obtenues selon la méthode préconisée par la Commission Technique 50 de la RILEM, dont on dispose, changent avec la taille de l'éprouvette, ce qui met en question la possibilité de considérer GF comme un paramètre du matériau. On a considéré, dans un article précédent, les sources possibles de dissipation de l'énergie due à l'équipemet d'essai et aux supports latéraux. On examine dans cet article-ci de nouvelles sources éventuelles de dissipation de l'énergie dans l'éprouvette, excepté celle de rupture proprement dite. Cette dissipation se produira dans la masse, dans les régions les plus contraintes de l'éprouvette et, si on n'en tient pas compte, on energeistrera des valeurs de GF plus élevées que celles strictement inhérentes à l'énergie de rupture superficielle. Si on considère cet apport et la dissipation d'énergie éventuelle analysée dans le travail précédent, ils ne suffisent pas à expliquer l'effet d'échelle mesuré. Si on doit considérer GF comme un paramètre du matériau, il conviendrait d'analyser avec plus de soin l'évaluation des résultats obtenus avec la méthode RILEM. De toute façon, l'énergie dissipée, dont on fait mention ici, représente une part non négligeable de GF et devrait être prise en compte dans les mesures.

Increasing competition and innovation in automobile sector tends to modify the existing products by new and advanced products. Today composite materials have changed all the material engineering. The evolution of composite materials has given an opportunity to various designers to use new and better materials resulting in cost reduction, increase in efficiency and better utilization of available resource. Most of the industries are using composite materials such as Epoxy resin, glass fiber and epoxy carbon. In this paper, the objective is to manufacture the composite lever clutch to replace the conventional aluminium lever clutch. The composite lever clutch will be compared the results with conventional lever clutch under different mechanical testing with evaluating of different mechanical properties such as tensile strength, bending strength, impact strength, fatigue strength by using appropriate experimental technique.

In this research, rice husk ash (RHA) —a carbon neutral waste product that is an abundant source of silica—was chosen as an innovative filler for epoxy paint. The influence of the RHA on different mechanical properties of the cured coatings (wear, hardness, and elongation) was investigated. Wear tests in pin-on-disc mode were carried out and followed by scanning electron microscopic observations to determine the wear mechanism for specimens with different values of carbon and silica according to their different colors as fillers for epoxy paint. Pencil hardness tests and bending tests were performed according to ASTM D3363 and ASTM D522 standards, respectively. Adding RHA (heat treated at 700°C) at two levels—10 and 20% weight fraction—to the unfilled epoxy paint increased the wear resistance, scratch resistance, and elongation of the filled coating compared to the unfilled epoxy coating.

ABSTRACT Friction stir welding (FSW) has been widely used to metals with moderate melting temperatures, primarily Al alloys. Recently, tool materials that withstand high stresses and temperatures necessary for FSW of materials with high melting temperatures have been developed. In the present Study tungsten carbide (WC) was used for FSW of dissimilar monel 400 alloy and 316 stainless steel, and a defect-free weld was successfully produced. Microstructural characteristics, and mechanical properties in the weld were examined. The work included microstructure examination, microhardness, tensile and fatigue tests of all joints. This study shows that the friction stir welded dissimilar joint present better mechanical properties when compared with each base material. Microhardness and tensile strength increased by more than 30% and 20%, respectively, as compared to base metal.

Available measures of the fracture energyG F obtained with the procedure proposed by RILEM TC-50 provide values that appear to change with sample size, calling into question the possibility of consideringG F as a material parameter. In previous papers several sources of energy dissipation were analysed and it was concluded that, although important, they were not enough to account for the measured size effect. Here, the dissipated energy at the very end of the test is analysed. It is shown that this energy cannot be neglected for small specimens if the tests are interrupted at a reasonably low rotation. When this energy is taken into account, the final values ofG F appear to be almost size-independent. This result supportsG F as a material parameter and provides further confidence in the RILEM proposal. Moreover, it furnishes a physical explanation for the perturbed ligament model previously developed by the authors. Les mesures de l'énergie de ruptureG F obtenues selon la méthode préconisée par la Commission Technique 50, dont on dispose, fournissent des valeurs qui se trouvent changer avec la taille de l'éprouvette, ce qui met en question la possibilité de considérer GF comme un paramètre du matériau. Dans les articles précédents, on a examiné plusieurs sources de dissipation de l'énergie, et on a conclu que, tout en ayant de l'importance, elles ne suffisent pas à explique l'effet d'échelle mesuré. Une solution semble résider dans le fait que, en flexion, l'essai ne peut être contrôlé jusqu'á rupture complète de l'éprouvette. Il doit être stoppé quelque part avant ce point, et la quantité d'énergie qui correspond au segment non enregistré de la courbeP-δ n'est pas prise en compte dans les mesures. Quand cette énergie est prise en compte, dans les résultats expérimentaux des auteurs, les valeurs, finales deG F semblent presque indépendantes de l'échelle. Ce résultat permet de considérerG F comme un paramètre du matériau à des fins de calcul, et constitue un encouragement pour la modélisation du béton en tant que matériau cohérent. L'énergie comprise dans le segmentP-δ justifie une explication physique du concept phénoménologique dit ‘Perturbed Ligament Model’ que les auteurs ont précédemment élaboré.

Non-destructive (ND) evaluation by thermographic analysis was applied to reinforced concrete (RC) beams strengthened with CFRP laminates, to assess the quality of the interface between reinforcement and substrate before and under loading, during laboratory bending tests. The proper algorithm for processing data acquired from the thermographic system was first selected by testing reduced-scale fiber reinforced polymer (FRP)-strengthened concrete slabs with

Polypropylene–wood fiber composites were prepared in the optimal mixture conditions determined in a previous work (180°C, 60 rpm, 10 min). Tensile, impact and three-point bending tests were performed in order to evaluate the adhesion between matrix and wood fibers. Other than mixture conditions, drying temperature of treated wood fiber is also an important factor to obtain good performance composites as shown in this work. Tensile properties of composites submitted to two extreme conditions (immersion in water at ambient temperature for 90 days and immersion in boiling water for 1 h) were determined. Heat deflection temperature and thermal analysis of composites were evaluated.

Reliability test is a very important step for any electronic products before they can be sold to the market. In the previous decades, various types of test have been developed. One of the widely used testing methods is the board bending test. A major issue of performing a reliability test is that numbers of testing samples are required since the test has to be repeated until consistent and satisfactory results can be obtained. A long time will be spent on the specimen design, the assembly processes and the testing procedures. In case the reliability test is not satisfied, the specimen will need to be redesigned, reproduced and retested. This is costly and not efficient from the commercial point of view. To simplify the reliability testing process, computational simulation is proposed to predict the reliability of printed circuit board assemblies (PCBA) at the early design stage. In the present study, 3-point bending test is the reliability test adopted. Finite element model validation and two case studies regarding the application of the model are the objectives of this work. Comparison between experimental results and computational results is carried out for model validation. The physical properties (stiffness and strain) of the model show a good agreement with the experiments at both the elastic deformation stage and the plastic deformation stage under the 3-point bending condition. The maximum von Mises stress at the solder joints of the model at which the samples are found to be failed is also very close to the strength of the solder. This further validates the model. For application, this stress data is used as a failure criterion to indicate whether a PCBA is reliable under different bending conditions