Numerical analysis of stiffened plates subjected to transverse uniform load through the constructal design method

When it comes to engineering, high performance is always a desired goal. In this context, regarding stiffened plates, the search for better geometric configurations able to minimize the out-of-plane displacements become interesting. So, this study aimed to analyze several stiffened plates defined by the Constructal Design Method (CDM) and solved through the Finite Element Method (FEM) using the ANSYS® software. After that, these plates are compared among each other through the Exhaustive Search (ES) technique. To do so, a non-stiffened rectangular plate was adopted as reference. Then, a portion of its steel volume was converted into stiffeners through the ϕ parameter, which represents the ratio between the volume of the stiffeners and the total volume of the reference plate. Taking into consideration the value of ϕ = 0.3, 75 different stiffened plates arrangements were proposed: 25 with rectangular stiffeners oriented at 0°; 25 with rectangular stiffeners oriented at 45° and 25 with trapezoidal stiffeners oriented at 0°. Maintaining the total volume of material constant, it was investigated the geometry influence on the maximum deflection of these stiffened plates. The results have shown trapezoidal stiffeners oriented at 0° are more effective to reduce the maximum deflections than rectangular stiffeners also oriented at 0°. It was also observed that rectangular stiffeners oriented at 45° presented the smallest maximum deflections for the majority of the analyzed cases, when compared to the trapezoidal and rectangular stiffeners oriented at 0°.

Stress Intensity Factors for a Non-Circular Hole with Inclusion Layer Embedded in a Cracked Matrix

The failure analysis of a non-circular hole with an inclusion layer embedded in an infinite cracked matrix under a remote in-plane uniform load is presented. In this study, a series solution of stress functions for both the matrix and inclusion layer is obtained using the complex variable theory in conjunction with the method of conformal mapping. The stress intensity factor (SIF) can then be determined numerically by solving the singular integral equation (SIE) for the interaction among different crack sites, material properties, and geometries of irregular holes with an inclusion layer. In particular, the failure behavior of composite structures associated with an approximately triangular hole and an approximately square hole with inclusion layers, such as those of oxides, nitrides, and sulfides, is examined in detail. The results demonstrate that a softer layer would enhance the SIF and a stiffer layer would restrain the SIF when a crack is near the inclusion layer. It can be concluded that crack propagation would be suppressed by a stiffer layer even when a micro-defect such as a hole resides in the inclusion layer.

Design of the Power of an Electric Lifting Motor for a Single Girder Bridge Crane with a 500 Kg Load Capacity

An electric hoist could be considered as the most important component of an electric overhead crane. Electric hoists are material handling equipment used for lifting, lowering, and transporting materials and products. They are powered by an electric motor and have a controller to adjust the lifting parameters. Three-phase induction motors are most often used as electric lifting motors for bridge cranes. This paper concerns the design of the power of the electric lifting motor for an electric hoist of the single girder bridge crane with the 500 kg load capacity. It represents the design of the electric lifting motor according to a commonly used scheme for the design of electric motors, from the power at a uniform load to the relative load of the motor. Based on the input data, the necessary motor parameters are calculated using Microsoft Excel. The main parameter is the static power of the motor, the calculated value of which is 0.823 kW. Based on the value of this power, a three-phase induction motor 1.1 kW, MS90-4 is selected. This electric lifting motor is suitable for the above-mentioned bridge crane, as it meets the condition of torque overload.

Preliminary Design and Experimental Study of a Steel-Batten Ribbed Cable Dome

A steel-batten ribbed cable dome structural system is proposed. By replacing the upper flexible cables with semi-rigid steel battens, rigid roofing materials were conveniently installed overhead via non-bracket or less-bracket technology. Additionally, an 8 m diameter test model was designed, and a ‘ω’ shaped less-bracket consequent hoist-dragging system was adopted. Finally, the test model was tested under symmetric and asymmetric uniform loading arrangements, while a finite element model was established to verify the test values. The results indicate that the measured values are basically consistent with the finite element values. In the early steps of hoisting and dragging, the structure establishes a prestress, accumulates stiffness, and found its internal force balance, while the entire structure keeps a “ω” shape to guarantee stability. As the internal forces of the components increase, the structure turns from “ω” to “m” and finally reached its designed shape. With increasing symmetric uniform load, the internal forces of the cables decrease, the bending stresses of the steel battens increase, and the steel battens remain in the elastic stage. Under an asymmetric uniform load, the high loaded area is displaced downward, and the low loaded area behaves upward, twisting the overall structure.

An Experimental Study on Cold-Bending Stress and Its Reverse-Coupling Effect with the Uniform Load on Cold-Bent SGP Laminated Glass

SentryGlas® Plus (SGP) laminated glass is a novel type of safety glass with high strength and stiffness. On the other hand, cold bending is a novel technique to build curved glass curtain walls, and is advantageous in terms of its greater energy efficiency and cost-effectiveness as well as its simple construction processes. The cold bending of SGP laminated glass could result in broad applications for the material and provide huge economic benefits in the field of glass curtain wall construction. To study cold-bending stress and its reverse-coupling effect with the uniform load in SGP laminated glass panels, single-corner cold-bending tests, uniform load tests, and ultimate capacity tests were conducted on eight pieces of such panels with different cold-bending curvatures and interlayer thicknesses. The results revealed that cold-bending stress in the glass panels under single-corner cold bending demonstrated a saddle-shaped distribution, with the maximum and second-largest cold-bending stresses located near the corner of the short side and the long side adjacent to the cold-bending corner, respectively. The cold-bending stress and coupling stress increased nonlinearly as the cold-bending curvature rose and the interlayer thickness became greater. Moreover, cold-bending curvature was a factor that affected the cold-bending stress and coupling stress more significantly than the interlayer thickness. The ultimate capacity and ultimate deflection of the glass panels decreased as the cold-bending curvature and interlayer thickness grew.

ScD of Computer Science. Load balancing method in SDN networks based on ACS with improved dynamic resiliency

The article discusses the topical issue of load balancing in distributed computing systems. The analysis of existing solutions is carried out, tasks, problems and practical significance are determined. An improved balancing method using the checkpoint method and an additional confidence factor is proposed, which made it possible to ensure a uniform load on the controllers, while maintaining an acceptable level of efficiency. An assessment of the performance and comparison of the proposed method with existing methods is carried out, as well as steps for further research are indicated.

Study on mechanical behavior and damage process of concrete with initial damage under eccentric load

In order to analyze the influence of eccentric load on mechanical properties and damage process of concrete with initial damage, the eccentric load compression tests of concrete under different confining pressures were carried out with the help of PFC particle flow program. The results show that: the eccentric load does not change the relationship between peak stress, crack initiation stress and confining pressure of concrete under uniform load, but decrease the value of them. The peak stress increasing coefficient under uniform load is higher than that under eccentric load, and the peak stress increasing coefficient increases in a linear function with the confining pressure, and the increasing rate is approximately the same. Under uniaxial compression of eccentric load, a type I shear crack approximately parallel to the loading direction is formed, while under biaxial compression, a bending type shear crack with the lower tip of the initial crack as the inflection point is formed. The number of microcracks in concrete under uniform load and eccentric load can be divided into three stages: the calm period at the initial loading stage, the pre-peak expansion period from crack initiation point to peak point, and the rapid increase period after the peak.

Investigation of the effect of the angle between femoral and prosthesis mechanical axes on bone remodeling of femur in total knee arthroplasty

The bone remodeling is the process in which the bone adapts its structure to the variation of environmental loads. The joint might be broken or damaged as a result of aging or an accident. To remedy this situation, Total Knee Arthroplasty (TKA) and prosthesis implantation is recommended. The main goal of this research is to investigate the effects of femur implanting angle on the bone remodeling process after TKA in the Coronal, Sagittal and horizontal planes over seven years. First, the 3D CAD model from CT images is created then the bone behavior is simulated using a model with a USDFLD subroutine. The results show that as the implant rotates in one direction, the stress and density distribution increases in the same direction whereas the load and consequently the bone density decrease substantially in the opposite direction. Consequently, the bone density might even decrease 77 and 31 percent in the coronal and sagittal plane respectively, so in the total knee arthroplasty, the mechanical axes of prosthesis and femur should be parallel. The active bone which occurs as a result of mechanical axes of prosthesis and femur parallelism and consequently uniform load distribution, can protect the implant from prosthesis loosening and fracture.

Study on the mechanical response of anticlastic cold bending insulating glass and its coupling effect with uniform load

Cold bending is a characteristic of significance for the beautiful curved glass curtain walls, because it affects them in terms of energy-efficiency and cost-efficiency. The increasing engineering projects call for more special studies on the mechanical properties of cold-bent glass panels, especially when the walls are built by insulating glass that is currently widely used while its relevant research is very scarce. This paper is devoted to studying the mechanical properties of anticlastic cold-bent insulating glass while taking different factors into consideration, including glass thickness, cold-bent torsion rate and cavity thickness. 9 pieces of insulating glass were manufactured for anticlastic cold-bending test and their coupled effect with identical load is also studied, and numerical finite element analysis sessions were carried out to simulate the experimental results for each one of them. Further, we analyzed the stress distribution performance of the sample pieces under cold bending and a uniform load, followed by discussions about stress transfer controls in glass plates. The results showed that the cold-bent control stress is on the surface with direct loads from cold bending and close to the cold-bent corner on the short edge, and it is transferred from the parts around the corner to the center when the uniform load plays a leading role in generating stress. This transfer could occur under a relatively small load with a small cold-bent torsion rate. A higher cold-bent torsion rate in cold bending contributed mostly to greater center stress in the glass, and as the glass thickness grows, stress and deflection at the plate center would significantly drop. However, the effect of cavity thickness on the anticlastic mechanical response of insulating glass was found to be trivial.