Experts have always desired to obtain materials with the desired properties or required constituents. The optimization of microstructures is considered to ensure optimal mode and accurate calculations. Microstructures, as heterogeneous materials, undergo an optimization process to optimize their structure. In this article, we implement topology optimization design for multiphase elastic microstructure using a compensation factor and numerical homogenization method. During the study, numerical optimization is performed by applying calculations on design changes consisting of the volume percentage of each phase in each element. The technique used to solve the topology optimization problem involves dividing it into several series of two-phase subproblems, with a conventional two-phase operator used in the optimization space. In this research, we obtained values of 0.7264, 0.4447, and 0.3008 for shear modulus, bulk modulus, and axial stiffness, respectively. Generally, the calculation rate depends on the number of phases involved in the structure design process. Previous studies have addressed this question for symmetric, symmetrical, and two-phase microstructures. However, in this study, we address this design problem by creating tensors of material properties as a function of the volume percentage. This approach is achieved by defining a design space and establishing regular upper and lower boundaries for local features. These boundaries are maintained to ensure consistency and standardization in subsequent works related to multiphase microstructure design.

Experts have always desired to obtain materials with the desired properties or required constituents. The optimization of microstructures is considered to ensure optimal mode and accurate calculations. Microstructures, as heterogeneous materials, undergo an optimization process to optimize their structure. In this article, we implement topology optimization design for multiphase elastic microstructure using a compensation factor and numerical homogenization method. During the study, numerical optimization is performed by applying calculations on design changes consisting of the volume percentage of each phase in each element. The technique used to solve the topology optimization problem involves dividing it into several series of two-phase subproblems, with a conventional two-phase operator used in the optimization space. In this research, we obtained values of 0.7264, 0.4447, and 0.3008 for shear modulus, bulk modulus, and axial stiffness, respectively. Generally, the calculation rate depends on the number of phases involved in the structure design process. Previous studies have addressed this question for symmetric, symmetrical, and two-phase microstructures. However, in this study, we address this design problem by creating tensors of material properties as a function of the volume percentage. This approach is achieved by defining a design space and establishing regular upper and lower boundaries for local features. These boundaries are maintained to ensure consistency and standardization in subsequent works related to multiphase microstructure design.

The conventional metal coil springs can be coated with a layer of rubber to improve the suspension characteristics of rolling stock in terms of stiffness capabilities and vibration attenuation. Here, by means of a hyperelastic finite element analysis and also introducing a modeling concept of three springs in parallel, the significance of mechanisms contributing to the axial stiffness of rubberized coil springs (RCS) are well disclosed. The stiffness share resulting from the rubber–, metal bonded interface was found to be remarkable (79% of the total RCS stiffness), much greater than the role played by a bare rubber or a metal coil spring. This contribution was elucidated by the stress field of shear-combined compression within the rubber layer. The model was the next ended to systematically examine the impact of material and structural factors influencing the RCS stiffness. In particular, the impacts of rubber hardness, rubber thickness, coil wire diameter, number of active coils, and coil outer diameter on the RCS stiffness were inspected. The rubber hardness significantly contributed to the axial stiffness of the part, while the rubber thickness revealed only a marginal effect. Interestingly, increasing the number of active coils though reduces the stiffness of the metal coil spring, it still augments the axial stiffness of the RCS.

The main target of this paper is to obtain an optimum wedge angle for best static and dynamic performance of a V-shaped clamp band separation mechanism. For this purpose, by using the finite element method, the proper 3D model for V-clamp band mechanism has been modelled and analysed in Abaqus/Explicit solver. In order to study the effect of wedge angle on bending and axial stiffness of V-clamp joint, many quasi-static analyses with different wedge angles were accomplished so the relation between wedge angle and axial stiffness of V-clamp joint under symmetric bending loading is extracted. In the next step, dynamic analyses were accomplished so the relation between wedge angle and separation time (duration between trigging moment and the time of disconnecting between flanges and wedged clamps) is extracted. For verification, this project results have been compared with the results of other researches and good agreement is observed. The results show that the optimal wedge angle for obtaining maximum stiffness together with minimum spring back disconnection time for the V-clamp band mechanism is 20˚ .

There are many industrial applications of axially grooved journal bearing, especially in turbo-machinery. Stability is a very big issue for researchers, in high speed rotating machines. The axial groove journal bearing has a capacity to reduce the vibration and the ability to resolve the heating problems as well as stability at a higher speed. Dynamic performance parameters and stability of axial grooved hybrid journal bearings depend on the dimensions and orientations of the groove to a great extent at higher speeds. In this work, a FORTRAN program is used to solve Reynolds governing equation. The bearing performance characteristics are simulated for the various dimensions and orientation of the groove. Non-linear journal center trajectories are drawn for different Reynolds numbers for stability analysis. It is found that the smaller groove length results in lower bearing capacity, whereas smaller groove width yields higher bearing capacity, and the turbulence decreases the stability. The groove location also strongly affects most performance parameters. The optimum location of the groove axis is obtained between 60° to 90° to the load line.

Use of adhesively bonded joints in structures has been increased in recent years because of their advantages. In structural applications, fatigue is generally considered to be the most important form of loading in respect to long-term service life. In this paper, experimental tests have been performed in order to examine the fatigue damage process of double lap adhesive joints, composed of E-glass laminates and epoxy adhesive with TiO2 P25 particles, under fatigue loading and then a method was proposed for fatigue life prediction based on initial stiffness. The scatter in results shows that the fatigue life is mostly dependent on initial stiffness. According to this, an exponential equation based on the initial stiffness has been proposed to have an initial estimation of fatigue life of the adhesive joints. In addition to the initial stiffness, stiffness degradation of the joints under fatigue loading influences on their final performance and therefore the initial estimation of fatigue life based on the initial stiffness could be modified. Also to have an online control of the fatigue damage process during the fatigue loading, a damage index using stiffness degradation was introduced.

Pipeline systems under thermal loads are frequently used in different industries, such as the power plants and petrochemicals. Unlike the analytical method of elastic center, which is capable to analyze only one branch of pipeline with pipe members parallel to the coordinate system, the method of stiffness removes these limitations. In this article the stiffness method is introduced for the analysis of pipeline systems. Based on this method, the piping system may include any number of piping braches. The straight pipe elements in the branch may have any general orientation and the bend elements may have any arbitrary angle. The computer program designed based on this method may compute the nodal displacements at the ends of the straight or bend elements and present three components for loads and three components for moments. Once the free-body diagram of each piping elements with nodal forces and moments are drawn, then the engineering codes are employed to design the piping system for safe operation.

The purpose of this review study is to review the studies that have assessed the interaction between surface stiffness and lower limb stiffness. There is a general hypothesis that with the increase of surface stiffness, the lower limb stiffness decreases or vice versa. These interactions take place with the aim of maintaining the dynamics of the center of mass and reducing the energy consumption during movement. One of the mechanisms for these interactions is the change in joint stiffness and leg geometry. Some studies suggested that the stretch reflex has no role in changing the lower limb stiffness. Although interactions between lower limb stiffness and surface stiffness has been recognized, there is little evidence about neuromuscular mechanism of these interactions. More studies is needed in this filed.

This paper deals with experimental results of an axial compressor of a small power plant gas turbine engine. Tests were carried out during the engine operation (along operating line of the compressor). Time averaged axial and radial pressure distributions in each individual stage were measured at different rotational speeds. Acceleration and deceleration phases of the engine were divided into reasonable time intervals of constant rotational speeds. Consequently, data logging was performed during steady operation of the engine. Measured parameters included pressure and temperature distributions and air mass flow rate. Test results were used to calculate axial distribution of load factor along the compressor mean line. Experimental results showed that the span wise total pressure reduces from mean line region towards the hub and casing at each stage. No significant variations in load factor of each stage were observed during acceleration and deceleration phases of the engine. Meanline load factor distribution was increasing from compressor head towards its end within experimental rotational speed range.