Static Structural Analysis Research Articles

Static Structural Analysis of Stainless Steel Based Skirt-To-Jacket Junction Using Design-By-Analysis Approach for a Vertical Jacketed Vessel

Static Structural Analysis of Stainless Steel Based Skirt-To-Jacket Junction Using Design-By-Analysis Approach for a Vertical Jacketed Vessel

Effect of vehicular vibrations on L-4 lumbar vertebrae – A finite element study

Lower Back Pain (LBP) is a global health issue, with increasing prevalence, partly attributed to vehicular vibrations experienced by motorcyclists. The L4 lumbar vertebra is responsible for greater mobility and flexibility of the body, but also is the most crucial body element affected by vehicular vibrations. Anthropometric properties, types of speed humps, and vehicle types are the critical variables that impact bone health during riding, need to be studied. To understand the potential zones of injury, computational simulation can be performed under the influence of vehicle vibrations while crossing different types of speed humps at varying speeds. In the present study, finite element method (FEM) is used to evaluate stress and deformation in the bone. The L4 cortical bone is modelled by considering the CT-Scan data and assumed to be homogeneous and isotropic material. Vibration data is collected using two vehicle types (Type I and Type II) on four different humps (Trapezoidal, Bitumen Semi-circular, Rubber Semi-circular, and Rumble strip). The bone's dynamic behavior is studied using FEM simulation, which involved static structural, modal and transient dynamic analyses. The findings from static analysis indicate that the most concentrated stress is located in the lower pedicle region and is an expected commonplace for injuries because of vibrations. In transient dynamic analysis, Type I vehicle showed a 25 % higher stress than Type II.

A Customized Distribution of the Coefficient of Friction of the Porous Coating in the Short Femoral Stem Reduces Stress Shielding

Stress shielding and aseptic loosening have been identified as adverse effects of short-stem total hip arthroplasty resulting in hardware failure. However, there is a gap in research regarding the impact of stress shielding in customized porous coatings. The purpose of this study was to optimize the distribution of the coefficients of friction in the porous coating of a metaphyseal femoral stem to minimize stress shielding. Static structural analysis of an implanted short, tapered-wedge stem with a titanium porous coating was performed with the use of Analysis System Mechanical Software under axial loading. To limit computational time, we randomly sampled only 500 of the possible combinations of coefficients of friction. Results indicate that the coefficient of friction in the distal lateral porous coating significantly affected the mid-distal medial femoral surface and lateral femoral surface. The resultant increased proximal strains resulted from an increased coefficient of friction in lateral porous coating and a reduction in the coefficient of friction in medial mid-distal coating. These findings suggest that a customized porous coating distribution may produce strain patterns that are biomechanically closer to intact bone, thereby reducing stress shielding in short femoral stems.

Evaluation of Load-Bearing Capacity in Japanese Arch Steel Aqueduct Bridge through Structural Redundancy Assessment

Structural redundancy assessment of steel aqueduct bridges is made by the analysis of a case study using the Musota Aqueduct bridge structure: a simply supported steel arch bridge erected in 1973 and a seven- span continuous steel aqueduct bridge. In this paper, as a case study, after the validation of the model, the structural redundancy of the Musota aqueduct bridge in Wakayama City with respect to its load-carrying capacity after the failure of hanging components due to corrosion was investigated. The conventional procedure for the assessment of redundancy makes use of static nonlinear structural analysis. A three-dimensional finite-element model of this bridge was developed to simulate its behavior. The results from the linear analysis are compared with those from the nonlinear analysis to investigate the appropriateness of the former in the evaluation of redundancy. A detailed nonlinear static finite element study is carried out into the hangers' components of the arch bridge in order to clarify the implications involved in the failure of redundancy. Finally, recommendations for prudent bridge maintenance methods are presented based on findings from the investigation.

Comparative Analysis of Boron-Al Metal Matix Composite and Aluminum Alloy in Enhancing Dynamic Performance of Vertical-Axis Wind Turbine

This study aims to assess the dynamic performance of the vertical-axis wind turbine (VAWT) with the help of conventional aluminum (Al) and the boron Al metal matrix composite (MMC). The simulations were conducted using ANSYS software and involved natural frequencies, mode shapes, a mass participation factor, and Campbell plots. The results of static structural analysis show that the boron Al MMC is vastly superior to the aluminum alloy because there is a 65% reduction of equivalent stress with a 70% reduction of deformation compared to the aluminum alloy. These results show that boron Al MMC can withstand higher loads with lesser stress; the structure remains compact and rigid in its working conditions. From the findings, it can be ascertained that employing boron Al MMC improves VAWT power, efficiency, and robustness. However, the critical speed that was established in the dynamic analysis of boron Al MMC requires extraordinary control and the use of dampening systems, thereby avoiding resonance. Overall, boron Al MMC contributes to significant enhancements in the VAWTs’ mechanical and operational characteristics; however, the material’s complete potential can be achieved only with proper maintenance and employing the correct damping techniques. Information about these two materials will allow for a better understanding of their comparative efficacy and their potential application in the further development of VAWTs.

Guidelines for Identifying the Structure of Heavy Phenolics in Lignin Depolymerization by using High-Resolution Tandem Mass Spectrometry.

The efficient conversion of lignin contributes to reducing human reliance on fossil energy. As a complicated biopolymer, studies on the mechanism of lignin depolymerization is limited by inadequate structural identification of high molecular weight (MW) products like heavy phenolics. Up to now, no individual method can generate both MW and structural information in operando conditions. As a promising approach, tandem mass spectrometry (MS/MS) techniques can provide structural information via the dissociation of target ions. In this study, MS/MS technique was performed both in offline and in-situ mode during lignin depolymerization. The fundamental guidelines based on MS/MS dissociation principles for typical inter-unit linkages like β-O-4, 5-5, β-β, β-5, and β-1 were well established. Based on that, major phenolic dimers are successfully identified, including chemical formula and types of inter-unit linkages. More significantly, real-time monitoring of structural evolution was achieved by applying in-situ MS/MS analysis during lignin depolymerization. The results show the different evolution pathways of isomers with same chemical formula, confirming that structural changes during lignin depolymerization are common and obvious. Overall, this study develops an advanced strategy for the full-view analysis of lignin depolymerization, achieving the static analysis of composition and structure, both monitoring the dynamic evolution of structures.

A Comparison of Free and Mapped Meshes for Static Structural Analysis

Abstract This study addresses the challenge faced by Finite Element Analysts when choosing between free and mapped meshes, especially in terms of convergence stability and solution accuracy. The investigation focuses on 3D solid models under static structural loading, analyzed using Ansys® and MSC Patran®. Both free and mapped mesh types, employing equivalent 3D solid elements, are used to assess an aircraft structural component under design load conditions, with fixed boundaries. For free meshes, Tet10 elements in Patran (equivalent to Solid 72 in Ansys) are used, whereas for mapped meshes, CPENTA / CHEXA elements in Patran (equivalent to Wed6 / Hex8 in Ansys) are employed. Mesh convergence studies ensure that discretization does not affect the numerical solution. Notably, a significant stress increase is observed with successive refinement of free meshes, while mapped meshes achieve mesh independence at coarser refinement levels. Comparison of fringe plots indicates the same location for maximum deformation and equivalent stress in both free and mapped mesh models. The findings demonstrate that free meshes tend to underpredict maximum deformation and equivalent stress compared to mapped meshes, with both meshes showing deformation and stress at consistent locations. The findings underscore the importance of carefully choosing the appropriate mesh type, particularly when analyzing critical structural components, to ensure reliability and accuracy in FEA simulations.

Design and Failure Analysis of Piston Using Ansys

A piston is a component of reciprocating engines. The purpose of piston is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and a connecting rod. It is one of the most complex components of an automobile. In This project we are describes the Thermal analysis by using finite element method (FEM). The specifications used for designing the piston belong to four stroke single cylinder engine of piston. Modeling of piston is done using SOLID EDGE v20. static structural, Thermal and fatigue analysis is performed by using ANSYS WORKBENCH 2022 R1. The parameters used for the simulation are operating gas pressure, material properties of piston. The results predict the maximum stress and strain on pistons using FEA. The best material is selected based on static structural, thermal and fatigue analysis. The analysis results are used to optimize piston geometry of best two Materials

Static and dynamic analysis of a hyperelastic toroidal air-spring structure

The present work proposes a novel toroidal air-spring model consisting of two cylindrical elastomeric membranes unlike conventional convoluted air-spring with one rubber bellow. The membranes are attached with two annular plates at top and bottom in circumferential direction, forming a closed space in between. With internally pressurizing the setup, the inflated bellow in the shape of a toroidal air-spring structure is formed. The static and dynamic analysis of the air-spring model is performed under transverse loading on top plate. The static analysis is carried out by compressing the air-spring to different suspension heights, assuming adiabatic compression of the enclosed air. The conditions for impending wrinkling, its prevention measures by choosing suitable design parameters, and the effect using cord-reinforced membranes are explored. The dynamic study under harmonic forcing is performed using the method of assumed modes coupled with a perturbation technique to solve the Eigenvalue problem of the discretized membrane structure. The radial asymmetric perturbations are included in the formulation to explore the symmetry breaking during dynamic study. The Eigen frequencies of the structure are obtained for different inflation pressures of the air-spring. Interestingly, a frequency veering phenomenon is observed between a few Eigen modes associated with closely spaced natural frequencies, where the possibility of mode swapping exists. The forced vibration analysis around a few Eigen frequencies shows beating like responses. The stiffness of the proposed air-spring is found to be linear under both static and dynamic conditions, which is inline with the stiffness nature of the convectional convoluted air-springs.

A quasi-zero-stiffness vibration isolator inspired by Kresling origami

Vibration isolators are widely used to mitigate undesirable vibrations in engineering systems and structures, but low-frequency vibration isolation remains a challenge. Origami-inspired structures, with their tunable stiffness and transformative capabilities, offer potential for vibration isolation. Inspired by conical Kresling origami, this study proposes a quasi-zero-stiffness vibration isolation system. Static analysis of the origami structure reveals that the system exhibits near-zero dynamic stiffness at the static equilibrium position, while maintaining static stiffness during the load-bearing process. The amplitude-frequency characteristic formula and vibration transmissibility formula are derived using the harmonic balance method. The effects of varying damping ratios and excitation amplitudes on the amplitude-frequency and transmissibility curves are examined. It is shown that the vibration isolation range increases with the number of layers. A comparison of the system's response to harmonic vibrations under different compressive deformations highlights the effectiveness of the origami quasi-zero-stiffness system as a vibration attenuator. Compared to existing quasi-zero-stiffness dampers, the origami-inspired system features a wider isolation frequency band, a lower initial isolation frequency, and reduced vibration transmissibility, demonstrating superior isolation performance, particularly at low frequencies.

Structural Reliability Analysis Using Stochastic Finite Element Method Based on Krylov Subspace

The stochastic finite element method is an important tool for structural reliability analysis. In order to improve the calculation efficiency, a stochastic finite element method based on the Krylov subspace is proposed for the static reliability analysis of structures. The first step of the proposed method is to preprocess the static response equation considering randomness to reduce the condition number of the coefficient matrix. The second step of the proposed method is to construct a Krylov subspace based on the preprocessed static response equation. Then, the static displacement of random sampling is expressed as a linear combination of subspace basis vectors to achieve the purpose of a fast solution. Finally, statistics and failure probability are calculated according to the static response obtained from thousands of random samples. Three numerical examples are given to compare the proposed method with the stochastic finite element method based on the Neumann series. The results show that the stochastic finite element method based on the Krylov subspace is more accurate and efficient than the stochastic finite element method based on the Neumann series.

A New Zero Waste Design for a Manufacturing Approach for Direct-Drive Wind Turbine Electrical Generator Structural Components

An integrated structural optimization strategy was produced in this study for direct-drive electrical generator structures of offshore wind turbines, implementing a design for an additive manufacturing approach, and using generative design techniques. Direct-drive configurations are widely implemented on offshore wind energy systems due to their high efficiency, reliability, and structural simplicity. However, the greatest challenge associated with these types of machines is the structural optimization of the electrical generator due to the demanding operating conditions. An integrated structural optimization strategy was developed to assess a 100-kW permanent magnet direct-drive generator structure. Generated topologies were evaluated by performing finite element analyses and a metal additive manufacturing process simulation. This novel approach assembles a vast amount of structural information to produce a fit-for-purpose, adaptative, optimization strategy, combining data from static structural analyses, modal analyses, and manufacturing analyses to automatically generate an efficient model through a generative iterative process. The results obtained in this study demonstrate the importance of developing an integrated structural optimization strategy at an early phase of a large-scale project. By considering the typical working condition loads and the machine’s dynamic behavior through the structure’s natural frequencies during the optimization process coupled with a design for an additive manufacturing approach, the operational range of the wind turbine was maximized, the overall costs were reduced, and production times were significantly diminished. Integrating the constraints associated with the additive manufacturing process into the design stage produced high-efficiency results with over 23% in weight reduction when compared with conventional structural optimization techniques.

Geometrically nonlinear static analysis of multi-component structures through variable-kinematics finite elements

Geometrically nonlinear static analysis of multi-component structures through variable-kinematics finite elements

Steady Heat Transfer Analysis of the Refrigerator Seal Considering Rigid and Flexible Contact

The rigid and flexible contact of the refrigerator seal has a significant impact on its heat transfer characteristics, but existing research has ignored this important factor. In this paper, the assembly physical model at the seal region is established by static structural analysis. Then a three-dimensional heat transfer numerical simulation is carried out. The assembly distance affects the contact state of the seal by changing the contact position between the seal and the door or the cabinet. The calculation results show that the calculated temperature at the seal region considering the actual assembly deformation is closer to the measured temperatures. In the case study, the heat leakage load decreases by 18.57% and 19.99% at the compressed state, while it increases by 4.45% under the stretching state. The proportion of heat transfer load in the path of rubber strip-cold air and rubber strip-outer shell of the cabinet is the largest, reaching over 30.0%. The heat transfer load of the cold bridge also accounts for over 20.0%. When optimizing the seal structure, reducing the contact interface length of rubber strip-cold air, reducing thermal conductivity, and increasing the contact thermal resistance of cold bridge should be focused on.

Development of an Underwater Adaptive Penetration System for In Situ Monitoring of Marine Engineering Geology.

In recent years, offshore wind farms have frequently encountered engineering geological disasters such as seabed liquefaction and scouring. Consequently, in situ monitoring has become essential for the safe siting, construction, and operation of these installations. Current technologies are hampered by limitations in single-parameter monitoring and insufficient probe-penetration depth, hindering comprehensive multi-parameter dynamic monitoring of seabed sediments. To address these challenges, we propose a foldable multi-sensor probe and establish an underwater adaptive continuous penetration system capable of concurrently measuring seabed elevation changes and sediment pore water pressure profiles. The reliability of the equipment design is confirmed through static analysis of the frame structure and sealed cabin. Furthermore, laboratory tests validate the stability and accuracy of the electrical and mechanical sensor measurements. Preliminary tests conducted in a harbor environment demonstrate the system's effectiveness.

A cable finite element formulation based on exact tension field for static nonlinear analysis of cable structures

This paper presents a numerically exact cable finite element model for static nonlinear analysis of cable structures. The model derives the exact expression of the tension field using the geometrically exact beam theory coupled with the fundamental mechanical characteristics of cables. The equations for the cable elements are formulated by addressing the equilibrium conditions at the element boundaries and ensuring compatibility within the elements. Unlike previous studies that typically provide explicit expressions for cable models, this study develops a formulation that emphasizes numerical precision and broad applicability. It achieves this by deriving linearized equations with implicit expressions incorporating integrals. The present model accurately computes internal forces and deformation states, and determines the unstrained length of the cable. Additionally, it accounts for the variability in cross-sectional stiffness along the cable's length. The paper discusses solution implementations using the complete tangent matrix and element internal iterations. The effectiveness of the proposed cable elements is demonstrated through numerical examples.

Artifact-free sample preparation of metal thin films using Xe plasma-focused ion beam milling for atomic resolution and in situ biasing analyses

The focused ion beam (FIB) technique using Ga ion beams is generally employed for transmission electron microscopy (TEM) sampling owing to its location-specific beam controllability on materials. However, Ga ion beam bombardment-induced damage hinders reliable structural analysis. Furthermore, Ga ions implanted in the damaged surface layer substantially lower the chemical stability of the samples, such as metal thin films. Here, aiming for atomic-level interface structural analysis, we propose a useful approach for the TEM sample preparation of heteroepitaxial Ag/Cu metal films without physical damage or chemical instabilities using the Xe plasma FIB (PFIB) system. Xe plasma-assisted sampling ensured that the interface structure of the Ag/Cu metal film remained intact; in contrast, the sample prepared using the focused Ga ion beam was damaged by elemental mixing. Furthermore, the sample prepared by Xe plasma milling exhibited robust structural stability over time after exposure to air in contrast to the sample prepared by Ga-ion milling, which induced structural decomposition owing to oxidation. In addition to the static structural analysis, the Cu thin film sample prepared by Xe PFIB exclusively exhibited pristine structural properties under in situ electrical biasing experiments, thus confirming the feasibility of conducting a fundamental study of Cu electromigration without artifacts.

Mixbiotic society measures: Assessment of community well-going as living system.

Social isolation and fragmentation represent global challenges, with the former stemming from a lack of interaction and the latter from exclusive mobs-both rooted in communication issues. Addressing these challenges, the philosophical realm introduces the concept of the "mixbiotic society." In this framework, individuals with diverse freedoms and values mix together in physical proximity with diverse mingling, recognizing their respective "fundamental incapacities" and uniting in solidarity. This study aims to provide novel measures to balance freedom and solidarity, specifically the intermediate between isolation and mobbing, within a mixbiotic society. To achieve this, we introduce simplified measures to evaluate dynamic communication patterns. These measures complement traditional social network analysis of static structures and conventional entropy-based assessments of dynamic patterns. Our specific hypothesis posits that the measures corresponding to four distinct phases are established by representing communication patterns as multidimensional vectors. These measures include the mean of Euclidean distance to quantify "mobism" for fragmentation, the relative distance change for "atomism" indicating isolation, and a composite measure derived from multiplying the mean and variance of cosine similarity for "mixism," reflecting the well-going state of a mixbiotic society. Additionally, nearly negligible measures correspond to "nihilism." Through the evaluation of seven real-society datasets (high school, primary school, workplace, village, conference, online community, and email), we demonstrate the utility of the "mixism" measure in assessing freedom and solidarity in society. These measures can be employed to typify communities on a radar chart and a communication trajectory graph. The superiority of the measures lies in their ability to evaluate dynamic patterns, ease of calculation, and easily interpretable meanings compared to conventional analyses. As a future development, alongside additional validation using diverse datasets, the mixbiotic society measures will be employed to analyze social issues and applied in the fields of digital democracy and platform cooperativism.

Nonlinear static analysis of masonry structures with mortar joints and cracking units by optimization‐based rigid block models

AbstractA rigid block model with elasto‐plastic softening interfaces is developed for nonlinear static analysis of masonry structures subject to monotonic loading. Cracking, crushing, and shear failures are taken into account at interfaces, following a simple micro‐modeling approach. An optimization‐based formulation is used for the solution of the equation systems governing the behavior of the rigid block assemblage. A simple incremental solution procedure is implemented to take into account the material softening behavior and the effects of large displacements on equilibrium conditions. The interface models are validated against tension and shear tests on bi‐block prisms from the literature. Applications to numerical and experimental out‐of‐plane loaded masonry walls as well as to circular arches with mortar joints are presented to evaluate the effects of tensile strength and the accuracy of the developed model against responses involving P‐Δ effects. Comparisons with experimental tests on shear walls also involving cracking of the units in the failure mechanisms are finally reported to discuss the potentialities and limitations of the proposed modeling approach.

3D electro-elastic static analysis of advanced plates and shells

The proposed three-dimensional (3D) coupled electro-elastic shell model allows the static analysis of smart structures embedding classical piezoelectric and functionally graded piezoelectric layers. Plates, cylindrical and spherical panels are investigated in both sensor and actuator configurations. The primary variables of the coupled model are displacement components and the electric potential. Therefore, displacements, stresses, strains, electric potential and electric displacements are calculated for smart structures used as sensors (applied mechanical load) and smart structures used as actuators (applied electric potential). In the case of spherical shells, 3D equilibrium equations are coupled with the 3D divergence electric displacement equation. The obtained coupled system is also valid for cylindrical shells and plates thanks to the use of a mixed curvilinear orthogonal reference system. The partial differential governing equations are solved using the Navier harmonic form and the exponential matrix method for simply supported structures. Preliminary assessments are proposed to validate the model and further benchmarks are analyzed to discuss the effects connected with the thickness ratio, the lamination scheme, the load conditions, the geometry of the structures and the employed materials. The main innovation point of the proposed model is the possibility to analyze several geometries including different materials and applied loads by means of a unique and general formulation where partial differential equations are solved in closed form. The use of functionally graded piezoelectric materials allows to eliminate all stress component discontinuities at each layer interface.