Uniform Load Distribution Research Articles

Experimental investigation of moving contact pattern in helical planetary gearboxes

Planetary gear sets combine the characteristics of high-power density and compact design which are beneficial for a wide range of high-performance applications. Embedded in the efforts for resource efficiency and cost reduction, new challenges arise regarding a lightweight design. An accurate prediction of the load sharing on the individual planetary gears and especially of the load distribution of the meshing gears is of major importance. A uniform load distribution enables the design of the individual tooth meshes without load increases and oversizing. However, a varying load distribution has been observed in planetary gearboxes with respect to the rotation of the carrier which is caused by misaligned central shafts of the gearbox. This behavior is influenced by several factors, such as manufacturing and assembly deviations, the rigidity of shafts, housing and bearings, the number of planets, the quality of the gear wheels and the operating conditions. To determine the exact load distribution, detailed simulations or extensive experimental prototype tests are required. In an early design phase, these detailed boundary conditions are not yet defined and their effect on a moving contact pattern therefore cannot be reliably considered.Thus, in this paper an experimental investigation of the influencing factors on a varying load distribution with regard to the carrier rotation is presented. Based on experimental data recommendations for the design of planetary gearboxes are derived.

Performance Analysis and Optimization of a Modified Stewart Platform for the Qitai Radio Telescope

This paper presents a modified Stewart platform that enables precise adjustment of the sub-reflector for the Qitai Radio Telescope (QTT). QTT demands a parallel platform capable of carrying a heavy load (≥4000 kg), and moving in elevation from 5° to 88° together with the primary reflector while precisely adjusting the sub-reflector’s position in five degrees of freedom. To meet these requirements, a modified Stewart platform with two separated actuators is proposed, and the comprehensive performance is analyzed and optimized for practical application. The performance of the modified platform is compared to that of the traditional Stewart platform, and the results demonstrate that the modified platform has superior load-bearing capacity and stiffness over the entire elevation angle with more uniform actuator load and stiffness distributions. These results indicate that the modified Stewart platform is well-suited for practical application in QTT.

Impact Dynamic Response of Spherical Net Shells: Finite Element-Based Computational Analysis Investigating the Influence of Dynamic Constitutive Models

The net shell is a widely utilized large-span space structure known for its aesthetically pleasing design and uniform load distribution, as well as serving as a prominent architectural landmark. In recent years, the impact resistance research of mesh and shell structures has garnered increased attention due to the accumulation of local conflicts. In this study, a parametric model of the spherical mesh shell was developed with Rhino software, and a numerical analysis model for a K8 mesh shell was established through the application of the ABAQUS finite element analysis software. Subsequently, the proposed numerical analysis method for the impact test was applied to validate its accuracy. The research also explored various dynamic constitutive models, such as Cowper-Symonds, Johnson-Cook, modified temperature term Johnson-Cook, and modified strain term and temperature term Johnson-Cook, with the assessment of their impact on the numerical simulation of impact resistance. Based on the impact dynamic response of the spherical net shell of different materials, the selection of an appropriate dynamic constitutive model for the numerical simulation of impact resistance in the spherical net shell was the MJ-C model. The comparative analysis of different materials, including Q235B, Q355B, Q460D, and 6061-T6, indicated that when the impact material failed to penetrate the structure instantly, the improvement of the material strength would enhance the impact resistance of the structure. On the other hand, when the impact material managed to penetrate the structure instantly, the material strength would not significantly help mitigate the damage. Notably, brittle materials, such as aluminum alloy, exhibited a distinct absence of a pronounced yield stage compared with low-carbon steel, which ultimately led to a relatively abrupt deformation.

Моделирование напряженного состояния концевой радиусной фрезы при формообразовании сложной поверхности

The paper presents results of simulating stress state in the cutting edge zone of the radial end milling cutter with the given tool orientation along the transverse angle. Simulation involved calculating the cutting forces in the ABAQUS program, converting them into loads acting on the tool surface, determining the contact zone of the tool front surface with chips based on the cutting theory and calculating stresses with the uniform load distribution in the considered tool section. Results of the preliminary calculations are provided. Distribution curves of the equivalent, normal and shear stresses in the cutting edge zone of the radial end milling cutter obtained using hardware of the ANSYS finite element analysis system were constructed. Simulation results allow further research to study the tool orientation and the cutting conditions influence on the tool stress state in shaping the complex surfaces. Determination of the machined surface zones, where the calculated stress values exceed the critical values, using the model makes it possible already at the initial stage of the technological process development to exclude destruction of the tool cutting edges and to achieve maximum productivity in shaping the complex surfaces.

Development of Membrane Reactor Coupling Hydrogen and Syngas Production.

Simultaneous syngas and pure hydrogen production through partial oxidation of methane and water splitting, respectively, were demonstrated by using mixed ionic-electronic conductors. Tubular ceramic membranes prepared from La0.5Sr0.5FeO3 perovskite were successfully utilized in a 10 M lab scale reactor by applying a radial arrangement. The supply of methane to the middle area of the reaction zone was shown to provide a uniform distribution of the chemical load along the tubes' length. A steady flow of steam feeding the inner part of the membranes was used as oxidative media. A described configuration was found to be favorable to maintaining oxygen permeability values exceeding 1.1 mL∙cm-2∙min-1 and long-term stability of related functional characteristics. Methane's partial oxidation reaction assisted by 10%Ni@Al2O3 catalyst proceeded with selectivity values above 90% and conversion of almost 100%. The transition from a laboratory model of a reactor operating on one tubular membrane to a ten-tube one resulted in no losses in the specific performance. The optimized supply of gaseous fuel opens up the possibility of scaling up the reaction zone and creating a promising prototype of a multitubular reaction zone with a simplified sealing procedure.

GENERAL ANALYTICAL EXPRESSIONS FOR DEFLECTION AND SLOPE OF EULER-BERNOULLI BEAM UNDER DIFFERENT TYPES OF LOADS AND SUPPORTS

In this research paper, we solve the Euler-Bernoulli beam (EBB) differential equations by taking the general boundary conditions. Instead of finding a solution for the EBB model for a particular load and its particular boundary conditions, we derive the general analytical solution with general boundary conditions by using techniques of integration. The proposed general analytical solutions are neither load specific nor dependent on specific boundary conditions but can be used for any load and any boundary condition without having to integrate again and again. We have taken a general polynomial load function with general boundary conditions, and get the general analytical solution for the deflection and slope parameters of EBB. We find the direct solution for uniform distributed load and linearly varying load for a fixed beam.

Static behavior of elastically supported transversely inhomogeneous porous functionally graded plate with different thickness variations under a variety of external loadings

The static behavior of a porous functionally graded material plate (FGMP) with variable thickness placed on two parametric elastic foundations exposed to various boundary conditions is investigated in this study. Thickness variation in the plate is assumed to vary in uni-direction/bi-direction with linear and parabolic variations. The properties of the constituent of FGMs are expected to change in the direction of thickness following the power law. The plate is subjected to three types of external loadings: uniformly distributed load (UDL), linearly increasing load (LIL), and linearly increasing decreasing load (LIDL). To explore the static behavior, numerical parameters (NP) linked with the bending and normal stresses of the plate have been determined. Classical plate theory is used to derive the governing equation using the energy principle. The transverse displacement functions are indigenously developed in the form of simple algebraic polynomials (using Pascal’s triangle) to handle any set of mixed- boundary conditions. The Rayleigh–Ritz method along with the algebraic polynomial is employed in the numerical simulation for getting NP. This method is straightforward, precise, and computationally efficient as it can handle any set of boundary conditions and the solution converges with very few iterations. Following the convergence and validation analyses, new findings are presented. The influence of aspect ratios, power-law exponents, porosity volume fraction, taper ratios, and the Winkler and Pasternak modulus on the NP of the plate has been thoroughly examined. The effect of various types of external loading and boundary conditions on deformed shapes and co-ordinate of maximum deflection of elastically supported porous FGMP with different thickness variations have also been reported. One of the important findings is that the effect of homogeneous porosity distribution on NP is more pronounced than in situations with non-homogeneous distributions. Also, the change in thickness of the plate and the distribution of various types of porosity has a substantial effect on the deformed shape of the plate. One of the interesting observations of this study is that the deformation in the plate is more significant in the case of bi-linear thickness variation compared to the uni-linear case. The results reported in this article are accurate enough to consider for further research and experimentation.

Research on the deep peak-shaving cost allocation mechanism considering the responsibility of the load side

With the goal of carbon reduction, China has carried out a series of institutional reforms and innovations in renewable energy consumption. However, the existing allocation rules for peak-shaving costs concentrate on the power side only. In the context of high energy penetration rates, peak-shaving cost significantly increases, and the economic pressure on the power side sharply increases. As the beneficiaries of peak shaving, the load side, while enjoying clean energy, also needs to bear the responsibility of peak shaving and share part of the peak-shaving cost. In this regard, this paper proposes a peak-shaving cost allocation mechanism considering load-side participation. First, it uses the marginal contribution theory to establish the peak-shaving value evaluation model of the power and load. Then, based on the waveform similarity theory, it sets two indicators “Fluctuation Trend Similarity” and “Waveform Amplitude Difference” to evaluate each load’s renewable energy consumption responsibility. Finally, the peak-shaving cost allocation rules on the power source side and the load side are obtained. An example shows that the proposed allocation mechanism can initially realize the uniform distribution of power and load in peak-shaving cost. Furthermore, the method can promote the fairness of the peak-shaving market and guide users to reasonably participate in the peak-shaving market.

A flexible bearing plate based on steel plate and rubber mat

The bearing plates used in plate load test for highway engineering are typically rigid. However, due to limitations in obtaining the accurate distribution of compressive stress at the bottom of the bearing plate, there is often a significant deviation between the measured subgrade resilient modulus and the actual condition. To address this issue, a flexible bearing plate can be used to test the subgrade and obtain a more accurate resilient modulus. In this study, we use variance and degree of mean deviation to quantitatively evaluate the distribution uniformity of compressive stress. To create a rigid-flexible bearing plate that is similar to a flexible bearing plate, we explore the combinatorial design of steel plates and rubber mats. We examine factors such as the thickness (10, 20, and 30 mm) of the steel plate, elastic modulus (5, 10, and 20 MPa) and thickness (10, 20, and 30 mm) of the rubber mat, friction coefficient (μ:0, 0,2, 0.4, 0.6, 0.8, ∞) between the bearing plate and subgrade, and the combined shape characteristics of the rubber mat and steel plate. To reduce friction between the rubber mat and subgrade, we use lubricant, and through our design process, we develop a flexible bearing plate with relatively uniform compressive stress. Our computations show that when μ = 0.05, the variance is 0.0001, and the degree of mean deviation is 0.0780. These results indicate that the distribution uniformity of the compressive stress is very close to the uniform distribution load, which meets the necessary accuracy requirements for engineering applications.

Simplified multi-scale simulation investigation of 3D composite floor substructures under different column-removal scenarios

The robustness of structures to withstand progressive collapse is a significant theme. However, owing to the restricted experimental conditions, some issues regarding 3D composite floor substructures under a column-removal scenario remain unclear, such as different column-removal scenarios, boundary constraints, loading schemes, floor numbers, reinforced concrete (RC) floors, and structural or nonstructural components. To understand these issues, a progressive collapse study on 3D composite floor substructures subjected to uniformly distributed load (UDL) is carried out based on simplified multi-scale simulation. A 2 × 1-bay concrete-filled steel tubular (CFST) column-steel beam-RC floor substructure is employed to investigate the structural robustness under the corner column-, penultimate-edge column-, and middle-edge column-removal scenarios. It is found that the vertical resistance for the corner column-removal scenario is reduced by approximately 10–20% compared to the other two scenarios. The 3D substructure resists progressive collapse via the flexural action (FA), the catenary action (CA), and the RC floor. Compared with the real boundary constraints, the fixed and hinged supports at the beam ends can overestimate the CA, and disregarding boundary constraints can overestimate deformation performance. Moreover, the concentrated vertical load (CVD) severely underestimates the robustness of 3D substructures. The floor number, RC floor, shear wall, and steel brace significantly influence the progressive collapse performance of 3D substructures.

Lateral torsional buckling behaviour of tapered steel section with web opening – finite element analysis

PurposeRecently, this steel section has found increasing popularity in residential, industrial and commercial buildings with their high load-carrying capacity due to the nature of high strength to weight ratio properties. However, the rise on the price of steel section should be more emphasized; therefore, the optimization in steel section design is needed to overcome the issue of material cost. As such, tapered steel sections save on material use, while the introduction of web openings allows the placement of mechanical and electrical services, plumbing and also aesthetic design considerations.Design/methodology/approachThe purpose of this study is to investigate the lateral torsional buckling behavior of a tapered steel section with an ellipse-shaped opening by analyzing its structural parameters. To achieve this, the finite element analysis (FEA) of the section is modeled using LUSAS software, which allows for a detailed analysis of the section's behavior under varying loads and conditions. It involves the variation in web opening size, opening layout, opening rotation angle and the tapering ratio. Eigenvalue buckling analysis is adopted to know the parametric effects of each 108 model. The size of opening varies from 0.2 to 0.5 d of the total depth where the opening located. There are three type of layouts applied in this study, which are the layouts A, B and C. There are three types of rotation angles for the ellipse-shaped opening, including the non-rotated vertical opening and two additional types formed by rotating the opening 45 degrees clockwise and counterclockwise around the center-point of the ellipse. A fixed-free boundary condition was applied, resulting in a simulation of a cantilever beam. The models are fixed at one end with a larger depth, and free at the other end with a smaller depth. Loading condition is an application of 10 kN/m uniform distributed load in the direction of gravity along the mid-span of the top flange.FindingsIt is observed that the model 82 with Layout A, tapering ratio 0.3, opening size 0.5 d and opening rotated in 45 degree anti-clockwise direction results in the highest structural efficiency among the 108 models. Therefore, the buckling moment of model 82 is 1,013.08 kNm with structural efficiency of 481.26, which shows an increase of 3.17% compared to the controlled model.Originality/valueThe FEA results shows a significant increase in ductility and stiffness of the tapered steel section with elipse shape opening and consequently changes in the behaviour of yield point.

A brief introduction to the Matlab program

The paper aims just a brief introduction to the MATLAB software. In this article, we study three cases: right triangle, pendulum and simply supported beam. In the first case, we make a right triangle that has the following dimensions: 3m, 4m and 5m. Moreover, in the second case, we calculate the angle αt from a simple pendulum. In the last case, is determined shear force and bending moment only when the uniform distributed load act on the simply supported beam (SSB).

Structural Behaviour of Castellated Beam: A Review

The use of castellated beams has gained popularity due to their excellent performance in terms of strength, stiffness, and economy. Castellated beams are fabricated by cutting I-sections or H-sections along the web in the desired shape and re-joining the two halves on one another through welding in order to improve the beam's overall depth. Most often, hexagonal, circular, diamond, and sinusoidal shapes are used for the web opening. This pattern increases the surface area and reduces the weight of the beam without compromising its structural integrity. The idea incorporates the technique of offering the best section in accordance with the most essential need. This paper presents an overview of the behavior of castellated steel beams with several shape openings having an I-shaped cross-section, modeling is conducted using the finite element software package ANSYS14 and ABAQUS. With uniform distributed load and simply support conditions, an analysis is conducted. The investigation of various failure patterns and the deflection at the middle of the beam are done

A study on the effect of opening location on ultimate load capacity of an orthogonal solid slab

The aim of the research is to study the effect of the position of the opening on the ultimate load capacity of the orthogonal solid slab. A yield line theory is used for the prediction of the ultimate load capacity of an orthogonal concrete slab with and without rectangular corner opening subjected to uniformly distributed load (UDL). In this study, two locations of the opening are considered: the rectangular opening provided at the corner and the interior corner of the slab. All possible governing, geometrically admissible, collapse mechanisms were identified, virtual work equations were derived, and to solve the equations a computer program has been developed. The same aspect ratios of the slab and the opening, and opening sizes up to 0.4 times the slab length the were considered. Four boundary conditions of the slab with different opening sizes are considered to present the design charts for affine coefficients.

Оцінка потенційної прохідності автомобіля бездоріжжям: сучасна методологія та нормативна база

Based on the analysis of the research of the Eastern and Western scientific schools, it was deter-?ined that the basic provisions and known achievements of the Western scientific school should be the basis for the formation of a modern domestic scientific school in the field of design and operation of vehicles with high and increased cross-country ability. It is necessary to take into account the priority direction of the research data in the field of military auto equipment, and therefore the problem of the lack of detailed algorithms or methods of computerized calculation and evaluation of the speed characteristics of the movement of a specific car on various support surfaces, which can be applied to practical use. The modern trend of the gradual transition of the NATO armies to a new generation of vehicles with the appearance of new models is due to the improvement of anti-mine protection of the crew and passability. And so it was formed in the 60s. In the 20th century, the configuration of the MI requires changes in accordance with the modern development of structures and requirements for them in the conditions of mobile military operations. This also applies to the differentiation of the same value of the axle load factor in the axle load range from 1 to 6 t 9, in which about 90% of the fleet of modern armies is concentrated, into 3 separate values for axle loads. The calcu-?ations are based on the condition of uniform distribution of the nominal load on the axle, which is not always correct for specific designs, especially for different layout schemes (hooded or hoodless). The same circumstance is also characteristic of the second NATO-standardized indicator of the vehicle’s structural passability, which elimi-?ates the real differences in the mobility of the same type and small-sized cars. Based on the review and analysis of modern research in the field of cross-country mobility and off-road mobility, the main provisions for the formation and assessment of the layout and suspension of high and increased cross-country cars and the conditions for maximum cross-country mobility, as well as the corresponding national standard, are presented. Keywords: off-road, vehicle, performance, mobility of movement, layout, suspension, standard.

Size-dependent fracture analysis of Centrally-Cracked nanobeam using Stress-Driven Two-Phase Local/Nonlocal integral model with discontinuity and symmetrical conditions

A novel mathematical formulation is presented to deal with stress-driven two-phase local/nonlocal integral model (SD-TPNIM) with discontinuity and symmetrical conditions, which is transformed equivalently into the differential form together with four constitutive constraints. Compare with classic SD-TPNIM, two extra constitutive continuity conditions are introduced, and a few integral items are introduced to constitutive discontinuity conditions and constitutive boundary conditions at symmetrical point. SD-TPNIM with symmetrical or anti-symmetrical conditions is applied to formulate the size-dependent fracture behavior of simply-supported and clamped–clamped centrally-cracked nanobeams subjected to uniformly distributed load (UDL) or middle point force (MPF) along opposite (Mode I crack) or same (Mode II crack) directions. The bending deflections are deduced and expressed in explicit form for different boundary and loading conditions. Accordingly, one can calculate the work done by external loads and energy release rate for both mode I and II crack problems. In addition, the asymptotic solutions for energy release rate are deduced for small nonlocal length parameter. The influence of nonlocal parameters on the size-dependent fracture behaviors including external work and energy release rate as well as the accuracy of asymptotic solutions for energy release rate is investigated numerically. The size-dependent fracture behavior can explain the superior fracture performance of nanomaterial to some extent.

An Engineered Design of Self-Assembly Nanomedicine Guided by Molecular Dynamic Simulation for Photodynamic and Hypoxia-Directed Therapy.

To overcome the hypoxia barrier in tumor therapy, a hypoxia-activated prodrug of docetaxel (DTX-PNB) was synthesized and self-assembled with indocyanine green (ICG), forming a combination nanomedicine ISDNN. With the guidance of molecular dynamic simulation, the ISDNN construction could be accurately controlled, achieving uniform size distribution and high drug loading up to 90%. Within the hypoxic tumor environment, ISDNN exerted ICG-mediated photodynamic therapy and aggravated hypoxia to boost DTX-PNB activation for chemotherapy, enabling enhanced antitumor efficacy.

A New Shear Deformation Theory in Axiomatic Framework for Bending and Buckling Analysis of Cross-Ply and Angle-Ply Laminated Composite Plates

Abstract In this study, a new higher order hyperbolic shear deformation theory for mechanical analysis of cross-ply and angle-ply multilayered plates is developed. Analytical solution to the static and buckling responses of symmetric and anti-symmetric composite laminates is presented. The proposed theory considers secant hyperbolic function of thickness coordinate in the displacement field. Also the developed theory assumes non-linear distribution of displacements and ensures that the top and lower surfaces of the plates have zero shear stresses. The equilibrium equations are obtained by applying the principle of virtual work. The stiffness characteristics of cross-ply and angle-ply laminates are taken into account when solving these governing equations. The closed-form Navier solution satisfying the corresponding boundary conditions is derived for simply supported (SS) composite plates. The results for non-dimensional deflections, and stresses of composite laminates under the effect of sinusoidal and uniform distributed load are thus obtained. The uni-axial and bi-axial loading force are used to evaluate critical buckling loads. Furthermore, the impact of span thickness ratio, aspect ratios, fiber orientation, modulus ratio, etc. on static and buckling analysis plates is also studied. The validity of present formulation is demonstrated by comparing our results with some of the available results in the literature.

Bending Analysis of Composite Plate with Cutout Carrying Uniformly Distributed Load

Bending Analysis of Composite Plate with Cutout Carrying Uniformly Distributed Load

Ring-Split: Deadlock-Free Routing Algorithm for Circulant Networks-on-Chip.

This article considers the usage of circulant topologies as a promising deadlock-free topology for networks-on-chip (NoCs). A new high-level model, Newxim, for the exploration of NoCs with any topology is presented. Two methods for solving the problem of cyclic dependencies in circulant topologies, which limit their applications for NoCs due to the increased possibility of deadlocks, are proposed. The first method of dealing with deadlocks is universal and applicable to any topology; it is based on the idea of bypassing blocked sections of the network on an acyclic subnetwork. The second method-Ring-Split-takes into account the features of circulant topologies. The results of high-level modeling and comparison of the peak throughput of NoCs for circulant and mesh topologies using deadlock-free routing algorithms are presented. It was shown that a new approach for routing in circulants (compared to mesh topology) shows up to 59% better network throughput with a uniform distribution of network load.