The aim of this study is to investigate the influence of different heat inputs on mechanical properties and microstructure of dissimilar electrical arc welded austenitic stainless steel AISI 304 and low-carbon steel (CS) joints. The mechanical properties of welded austenitic stainless steel type AISI 304 and low-CS are studied. Five different heat inputs 0.5, 0.9, 1.41, 2, and 2.5 KJ/min were applied to investigate the microstructure of the welded zone and mechanical properties. The results showed that the efficiency of the joints and tensile strength increased with increasing heat inputs, while excess heat input reduces the efficiency. Furthermore, changes in microstructure with excess heat input cause failure at the heat-affected zone.

In this study that spur gears are chosen, contact stress of spur gear is presented under the effect of rotational speed. Three-dimensional simulation of dynamic analysis of gears designed and modeled using ANSYS software. The dynamic analysis included in the determination of dynamic stresses analysis. Contact stress is theoretically calculated and analyzed and numerically estimated using both Hertzian mathematical model and finite element method respectively. Different values of rotational speed used to study its effect on contact stress. Both methods compared by evaluating the percentage error of contact stress, and the modeling of the spur gear and stress analysis of spur gear carried out using SOLID WORK and ANSYS V14, respectively. The most significant note in this study concludes that increasing speed causes vibration and pitting failure due to repetitions.

This study deals with the Rotary Friction Welding, (RFW) as a variation of friction welding in which the energy required to make the weld is supplied primarily by the stored rotational kinetic energy of the welding machine. The mechanical energy generated in overcoming friction is continuously transformed into heat. In most circumstances the thermal energy generated is regarded as undesirable, but under controlled conditions it can be used to join materials, as in the case of rotary friction welding. In this paper, similar and dissimilar joints of Acrylonitrile butadiene styrene (ABS) (chemical formula (C8H8)x· (C4H6)y· (C3H3N)z) and Polyethylene (PE) or polyethene or poly(methylene)) are studied. The effects of different rotational rates, plunge depths, and traverse speeds on the microstructure and tensile strength of joints were investigated. Some defects such as pores and cracks were found at inappropriate processing parameters. The tensile test was carried out as the mechanical properties of joints. Different significant parameters were discussed. The maximal and minimal tensile strength indicated and evaluated.

Hybrid fiber reinforced polymer with nanofiller composite was introduced into a lot of industries due to its extreme mechanical properties in comparison with non-hybrid material. In this investigation, cross and quasi-fiber laminated epoxy composites with and without nano Al2O3 were fabricated using Vacuum Assisted Resine Infusion Method and Ultrasonic Dual Mixing Method. In general, the results of mechanical properties indicated that the addition of 2% nano Al2O3 enhances the tensile and flexural properties. Cross number 2 with nano Al2O3 laminate had the maximum tensile strength 628 MPa and maximum tensile strain of 1.74%, while cross number 1 with nano Al2O3 laminate had the maximum tensile modulus of 37.756 GPa in the cross group. In the quasi group, quasi number 2 with nano Al2O3 had the maximum tensile strength, maximum tensile strain, and maximum tensile modulus, equal to 294 MPa, 1.98%, and 16.409 GPa, respectively. Regarding the flexural properties, cross number 1 with nano Al2O3 laminate had a maximum flexural strength of 708.2 MPa and maximum flexural strain of 2.027%, while cross number 2 with nano Al2O3 laminate had a maximum flexural modulus of 38.73 GPa in the cross group. On the other hand, quasi number 1 with nano Al2O3 laminate had the maximum flexural strength, maximum flexural strain, and maximum flexural modulus equal to 596 MPa, 2.424%, and 29.2 GPa, respectively in the quasi group. The internal structures of the failure laminated composites through scanning electronic microscopy confirm that the adhesion between fibers and matrix is good.

In this study, a comparative analysis is presented between a new proposed analytical model and numerical results for macroscopic behavior of porous media with isotropic hardening in its matrix. The macroscopic behavior of a sufficiently large representative volume element (RVE), with 200 identical spherical voids, was simulated numerically using finite element method and compared with elementary volume element that contains one void. The matrix of the porous material is considered as elasto-plastic with isotropic hardening obeys exponential law for isotropic hardening. A new parameter  was added with exponential law for isotropic hardening to represent the new proposed analytical model for macroscopic isotropic porous hardening. The new added parameter B depended only on the porosity. The results of the new proposed analytical model were compared with numerical results for different types of cyclic loading. Very good agreements were found between the numerical results and the proposed analytical model.