Finite Element Structural Analysis Research Articles

Research on Damage Detection of Dual-Rotor Synchronous Excitation Mine Screen Beams Based on Strain Mode Difference Vibration Mode Analysis

The frame beam structure of the mine screen, subjected to various excitations, is a critical component of mining machinery. Its stress is intricate, the operational environment is severe, and damage can lead to catastrophic failures resulting in machinery destruction and fatalities. Based on the characterization of the vibration response of mine screen frame beams with varying degrees of damage at the same location and with the same degree of damage but at different locations, this paper develops a method of strain modal difference vibration pattern analysis and damage feature extraction for the detection of structural damage in beams. This method is based on the sensitivity of the sudden change in vibration strain modal difference to small deformations. This method solves the problem of using the conventional structural finite element analysis or experimental modal analysis methods to obtain the displacement mode, intrinsic frequency, and other characteristics, which make it difficult to effectively identify the actual engineering, with the damage conditions of the damage state and damage location of the mine screen frame beam problems. The feasibility and validity of the engineering application of the concept are demonstrated through instances.

Construction of a deep basement with a single-level prop – prop forces and wall movements

This paper describes the construction of a deep basement in central London. The construction sequence for the basement was a combination of top-down and blue-sky excavation to enable phased delivery of the project. Temporary single-level props enabled blue-sky construction by managing ground movements. Ground movements associated with the basement construction and impact on third-party assets were monitored to validate the design using three-dimensional targets and inclinometers. The ground movements were predicted at each stage of construction using simple models with more complex three-dimensional soil–structure finite-element analysis used when examining the whole basement behaviour under the temporary and permanent loads. Temporary prop loads, and thermal loads on props were also monitored during the bulk digging. The small strain constitutive models for London Clay was shown to closely predict the observed movements.

Применение высокопрочной стали для создания полувагонов повышенной грузоподъемности

Purpose: substantiation of the possibility to increase the load capacity of gondola cars using high-strength steel in the car body structure. Methods: gondola cars load capacity changing analysis. Numerical research of the effect of the steel yield strength value on the mass of the beam structure according to the criteria of strength and stiffness for a beam on two hinged supports operating in bending, and also according to the buckling criteria of a compressed beam. Gondola car body structure finite element analysis in order to confirm the strength and buckling parameters with the normative requirements. Results: the analysis of load capacity of universal fouraxle gondola cars built in the period from the beginning of production of the first Russian cars up to the present time was performed. Results of the analysis of the effect of steel yield strength on the mass of the structure according to the strength criteria and stiffness for a beam on two hinged supports operating in bending, and also according to the buckling criteria of a compressed beam was presented. High-strength steel technical requirements for welded structures of freight wagons is considered. Parameters for evaluating the suitability of rolled high-strength steel for freight wagon construction are given. The results of strength and stability analysis of the gondola car model 12-6744 with high-strength steel, which confirm the design compliance of the car in terms of normative parameters of strength and stability with the requirements of the existing standards are given. The gondola car model 12-6744 advantages are described, as well as the economic effect of its operation for the consignor. Practical importance: the possibility of using high-strength steel to increase the load capacity of gondola cars is substantiated. The gondola car model 12-6744 with high-strength steel was designed. Its advantages are given, and the economic effect of operating such a wagon for the consignor is shown.

Exploring FEA Techniques for Bending Rectangular Glass Plates into Parabolic Shapes

Abstract: A structural Finite Element Analysis (FEA) was conducted, incorporating both linear and nonlinear analysis. The investigation considered geometric nonlinearity, material nonlinearity, and boundary nonlinearity, also known as contact analysis. All boundary conditions, loadings, and material properties used in the analysis were based on real-world conditions. Experimental validations were performed to confirm the accuracy of the FEA results, providing strong confidence in the investigation's findings.

Electromagnetic–Structural Finite Element Analysis of Copper and Aluminum Windings in Power Transformers under Short-Circuit Conditions

Electromagnetic forces can lead to the structural failure of power transformers due to extreme loading conditions, vibration, and/or fatigue. Therefore, studying the nature and the magnitude of these forces is a key task in the design and failure analysis of such important equipment. Keeping this issue in mind, this work aims at conducting a numerical analysis in order to evaluate the mechanical stresses and displacements of windings in power transformers due to the action of electromagnetic forces. With this purpose, a finite element model is developed considering electromagnetic and mechanical effects assuming short-circuit conditions. The study compares the cases employing copper and aluminum windings with header tap, in different temperatures. The model developed in this work is verified against analytical solutions. The numerical calculations allow for performing a detailed analysis in terms of the distribution of both displacements and stresses along the windings, which is of great relevance for identifying critical structural points and avoiding structural failure. Overall, the obtained results demonstrate that the finite element model is a useful tool for the structural design of power transformers that allow for investigating and optimizing key aspects before manufacturing.

Bond performance and constitutive model of steel bar in G-UHPC under cyclic loading

The increasing embrace of the low-carbon and environmentally sustainable construction approach has opened exciting opportunities for using environmentally friendly geopolymer based ultra-high-performance concrete (G-UHPC) in engineering structures, drawing significant attention to its performance. Seismic performance is a crucial factor in structural design, and it is greatly affected by the bond behavior between steel bar and concrete. As a result, a thorough understanding of the bond behavior of steel bars to G-UHPC provides essentially theoretical support for the structural design and nonlinear finite element analysis of G-UHPC structures, which is vital for their widespread implementation in earthquake engineering. This study tested 54 specimens from 18 groups to examine the bond performance of G-UHPC and steel bars under cyclic loading. The influence of concrete and steel bar types, protective layer thickness, bond length, and steel fiber on critical bond performance indicators were evaluated, and the bond stress-slip hysteretic and skeleton curves were analyzed. Subsequently, based on the experimental data, a constitutive model was proposed to predict the bond stress-slip relationship of steel bars and G-UHPC under cyclic loading. The results indicated that the steel bars exhibited superior bond performance with G-UHPC as compared to NSC. The bond and residual strength between steel rebars and G-UHPC was approximately 1.73 times and 3 times greater, respectively, in comparison with that between NSC and steel rebars. Increasing the strength of steel bars only resulted in a limited 2 % improvement in bond strength. The steel bar diameter, protective layer thickness, bond length, and the dosage and length of steel fibers in G-UHPC significantly influenced the bond performance. The addition of irregular-shaped steel fibers to G-UHPC has demonstrated potential in improving energy consumption, with the most remarkable enhancement observed for the inclusion of twisted steel fibers. Specifically, the incorporation of twisted steel fibers signally enhanced the energy consumption to approximately 1.3 times the energy dissipation as compared to straight steel fibers with the same dosage and aspect ratio. In addition, the accuracy of the proposed constitutive model has been validated.

Co‐reinforcing sustainable graphenes from thermoset/thermoplastic wastes for enhanced polypropylene matrix composites in automotive engineering

AbstractTalc is widely used in the automotive industry as a primary reinforcement in part manufacturing. However, its relatively high density, low impact strength, and difficulty in recycling pose challenges. The present study investigates the utilization of graphene grown on talc derived from waste polypropylene (PP) and graphene nanoplatelet obtained from waste tires by recycling and upcycling processes to be used as reinforcing agents in thermoplastic processing by keeping mechanical integrity and part performance properties the same compared to the part used in serial production. The whole value chain was examined by developing compound formulation, scaling up with a high shear mixer, and injection molding of the selected exterior part of the glass front grill with its part performance tests with the real‐case thermal and structural finite element analysis. Regarding the mechanical performance analysis, the developed compound formulation having 9 wt% micron scale talc with graphene nanoparticles and hybrid additive yielded substantial enhancements of 32% and 22% in flexural and tensile strength, respectively, in the homopolymer polypropylene (HomoPP) matrix by achieving 10% weight reduction. With a systematic life cycle assessment study, CO2 reduction was provided by 55% for the selected part by replacing virgin HomoPP with mechanically recycled waste PP originally unknown.

Digital Tools for the Preventive Conservation of Built Heritage: The Church of Santa Ana in Seville

Historic Building Information Modelling (HBIM) plays a pivotal role in heritage conservation endeavours, offering a robust framework for digitally documenting existing structures and supporting conservation practices. However, HBIM’s efficacy hinges upon the implementation of case-specific approaches to address the requirements and resources of each individual asset and context. This paper defines a flexible and generalisable workflow that encompasses various aspects (i.e., documentation, surveying, vulnerability assessment) to support risk-informed decision making in heritage management tailored to the peculiar conservation needs of the structure. This methodology includes an initial investigation covering historical data collection, metric and condition surveys and non-destructive testing. The second stage includes Finite Element Method (FEM) modelling and structural analysis. All data generated and processed are managed in a multi-purpose HBIM model. The methodology is tested on a relevant case study, namely, the church of Santa Ana in Seville, chosen for its historical significance, intricacy and susceptibility to seismic action. The defined level of detail of the HBIM model is sufficient to inform the structural analysis, being balanced by a more accurate representation of the alterations, through linked orthophotos and a comprehensive list of alphanumerical parameters. This ensures an adequate level of information, optimising the trade-off between model complexity, investigation time requirements, computational burden and reliability in the decision-making process. Field testing and FEM analysis provide valuable insight into the main sources of vulnerability in the building, including the connection between the tower and nave and the slenderness of the columns.

Synergy of LIDAR and hyperspectral remote sensing: health status assessment of architectural heritage based on normal cloud theory and variable weight theory

Architectural heritage health assessment is the basis of scientific repair and maintenance. However, existing methods do not adequately take into account the fuzziness, randomness and uncertainties unique to architectural heritage assessment. In this paper, a new evaluation model of VM-NCM is constructed by combining variable weight theory and normal cloud model theory. The model enables the combination of qualitative ratings and quantitative calculation, deals with the fuzziness in the assessment process, and resolves the randomness and reflects the uncertainty to a certain extent. Based on constructing the index system combining qualitative and quantitative indexes, the structural index values are acquired by the synergistic coupling of the fine laser point cloud model and finite element structural analysis model. The acquisition of surface index values is completed by the hyperspectral intelligent detection technology of surface materials and diseases. These reduce the generation of ambiguous information in the index detection process. An evaluation study is conducted using the Yingxian wooden pagoda in China as an example. The results show that this method takes into account the fuzziness and randomness in the evaluation process, and obtains more scientific and reliable evaluation results, which provides a research paradigm for assessing the architectural heritage health status.

An adaptive modeling method with a local choice of optimal displacement fields for finite element analysis of structures

In the standard finite element procedure, the user chooses himself which mechanical theory will be used for a given application. To this end, he relies on some rules acquired through experience or some theoretical consideration. But choosing an appropriate theory may be a difficult task when geometry, boundary conditions, loadings, and materials are complex. This paper aims to define an adaptive methodology to identify, in the context of linear static analysis, optimal finite element models from a theory choice point of view. A criterion is defined to choose, in each part of the structure, the relevant mechanical theory: solid, shell or beam. A solid mesh is defined for the whole structure while specific solid-shell or solid-beam approaches are used in shell or beam areas respectively. This avoids the construction of mid-surface or mid-axis geometries from solid ones, which is a complicated task, in particular for industrial applications. Kinematic relations between nodes are imposed to apply the displacement fields of shell or beam theories. This leads to a set of linear equations which are used for eliminating slave degrees of freedom. The methodology proposed can also be interpreted as a model size reduction method, compared to a complete solid approach. The effectiveness of this approach is demonstrated through two numerical examples, including academic cantilever structures and an industrial multilayered composite structure.

Structural design and finite element analysis of a milling machine sliding saddle

Abstract With the rapid development of modern manufacturing, the requirements for milling machine products are becoming higher and higher, leading to higher requirements for the working accuracy of milling machines. It is necessary to use the finite element method for static analysis of key components. This article uses 3D software to establish a geometric model of the milling machine saddle and establishes a finite element model. Finite element analysis is performed on the stiffness and strength of the sliding saddle in the middle of the crossbeam and the spindle sleeve at the lowest end of the sliding saddle under the load condition. Through analysis, it is known that the milling machine slide saddle is located in the middle of the crossbeam, and the spindle sleeve is located at the lowest end of the sliding saddle, which is the worst working condition. According to the strength theory, it is verified that its strength meets the requirements. This static analysis can provide reliable data for the design optimization of the milling machine saddle.

Optimizing plastic shredder rotor design through structural finite element analysis: A comprehensive approach using experimental design and response surface methodology

Shredder machines are essential for recycling plastic waste. They are used to shred plastic materials into smaller pieces, which can then be processed into new products. The shaft and rotary blades of the plastic shredder are its most crucial parts since they directly influence how effectively the machine shreds or recycles material. The shredder’s rotor is optimized based on the design of experiments and the response surface method. The natural frequencies and mode shapes are identified by modal analysis, and the critical natural frequencies that must be avoided during operation are identified through harmonic response analysis. The shredder’s rotor is optimized by determining its critical areas through a transient structural analysis. The optimization goals are attained by using the response surface method and experiment design in the ANSYS WORKBENCH DESIGN EXPLORATION module. The rotor of the optimized shredder is investigated, and its results are contrasted with the nominal design. The study of the optimum structure leads to a slight increase in mass of 2.43% in addition to reductions in equivalent stress and total deformation by about 9.84% and 42.86% respectively, as well as a 21.4%, 4.35%, and 4.48% increase in the first three natural frequencies, respectively.

Piston structure design and finite element analysis

The working characteristics of internal combustion engines rely on the explosive combustion of fuel in the combustion chamber to drive the piston movement. This working characteristic causes the main component of the combustion chamber, the piston, to bear high thermal and mechanical loads. It has very high requirements for design, manufacturing, and material selection. The working condition of the piston will affect its safety and stability. Therefore, the finite element analysis for the piston is particularly important. Thus, this article first establishes the piston model and divides it into grids in ANSYS, adds boundary conditions, and conducts analysis. The piston thermal analysis mainly includes thermal stress and deformation analysis under thermal load. The piston’s maximal thermal stress is 170.23 MPa and the deformation of thermal expansion is 0.61585 mm. The mechanical stress and deformation analysis under mechanical load are carried out. The maximal stress is 164.91 MPa and the maximal deformation caused by the mechanical stress is 0.24916 mm. Finally, the coupling analysis of thermal and mechanical stress is conducted. The maximal stress is 251.74 MPa, which is located at the outskirt margin of the piston pinhole. The maximal deformation is 0.60779 mm. The simulation analysis results indicate that the method proposed in this article provides a way to design the structure of similar automotive components such as pistons.

Biomechanical Evaluation of Plantar Pressure Distribution towards a Customized 3D Orthotic Device: A Methodological Case Study through a Finite Element Analysis Approach

Plantar pressure distribution is a thoroughly recognized parameter for evaluating foot structure and biomechanical behavior, as it is utilized to determine musculoskeletal conditions and diagnose foot abnormalities. Experimental testing is currently being utilized to investigate static foot conditions using invasive and noninvasive techniques. These methods are usually expensive and laborious, and they lack valuable data since they only evaluate compressive forces, missing the complex stress combinations the foot undergoes while standing. The present investigation applied medical and engineering methods to predict pressure points in a healthy foot soft tissue during normal standing conditions. Thus, a well-defined three-dimensional foot biomodel was constructed to be numerically analyzed through medical imaging. Two study cases were developed through a structural finite element analysis. The first study was developed to evaluate barefoot behavior deformation and stresses occurring in the plantar region. The results from this analysis were validated through baropodometric testing. Subsequently, a customized 3D model total-contact foot orthosis was designed to redistribute peak pressures appropriately, relieving the plantar region from excessive stress. The results in the first study case successfully demonstrated the prediction of the foot sole regions more prone to suffer a pressure concentration since the values are in good agreement with experimental testing. Employing a customized insole proved to be highly advantageous in fulfilling its primary function, reducing peak pressure points substantially. The main aim of this paper was to provide more precise insights into the biomechanical behavior of foot pressure points through engineering methods oriented towards innovative assessment for absolute customization for orthotic devices.

SEISMIC BEHAVIOR OF MULTI-STORIED RC BUILDING WITH RE-ENTRANT CORNER

Nowadays, buildings often feature irregular floor plans for functional, aesthetic, or economic reasons. Constructing earthquake-resistant structures in seismic areas, especially with irregular shapes like re-entrant corners, poses challenges. Such corners are common when maximizing limited space is a priority. In earthquakes, re-entrant corners in structures pose major vulnerabilities, causing stress concentration and torsion problems. The main aim of this paper is to develop finite element structural analysis models of 10, 12, and 15-storied L-shaped RC buildings with a re-entrant corner under different seismic zones using equivalent static analysis (ESA) and response spectrum analysis (RSA). This research also focuses on the overall behavior of analysis results (story drift, overturning moment, base shear, etc.) with the influence of re-entrant corner. It also investigates the performance of columns and beams near re-entrant corners as the number of stories increases in different seismic zones. For the current study, ETABS V19 is used. Models consider seismic, dead, and live loads. The Bangladesh National Building Code (BNBC) 2020 is used to examine the equivalent static analysis (ESA) and the response spectrum analysis (RSA) methods. It has been concluded from the study that re-entrant corner beams consistently exhibit the highest bending moments and torsion levels across all seismic zones. Similarly, re-entrant corner columns consistently demand the most axial force and rebar when compared to similar column types. Furthermore, the study identifies maximum stress levels in re-entrant corner slabs across all seismic zones.

Fire behavior of Automated Rack Supported Warehouses

The fire behavior of the automated rack-supported warehouse (ARSW) is a topic of great interest both for the scientific community and for the manufacturers of industrial racks. However, their behavior in case of fire of is still poorly known. ARSW is a particular type of steel racks that combine the structural efficiency of steel construction with automated machines for handling stored products. The paper investigates the fire scenario and the collapse mechanism of a typical ARSW by considering a fire model that allows vertical and horizontal propagation, starting from a localized fire, evaluated, and validated against experimental results. The study comprises two fundamental phases: fire simulation using a multi-zone model and investigation of the structural elements collapse through finite element structural analysis. An iterative procedure is proposed to correctly analyze the progressive mechanism of collapse by carrying out several subsequent implicit analyses with SAFIR software.

Fluid-Solid Interaction Analysis of a Flow Passing Cylinder Based on Variational Mode Decomposition

The fluid-structure interaction problem of cylindrical flow around the cylinder is a classic problem, especially in many fields such as energy engineering, fluid dynamics, engineering structure, energy utilization and development, and environmental protection. In this article, we have heard about the simplified model and analyzed it with the help of the classical cylindrical flow model. In this paper, the flow field was pre-processed on the Workbench software platform, and the pressure distribution and eddy current phenomenon were observed by post-processing given the velocity of the flow field of 1m/s. There is a large number of thunder (2.799552×106) and the Carmen Vortex appears around the cylinder. The vortex falls off periodically, and the wake structure is relatively irregular. The maximum pressure appears at the bottom of the cylinder and the maximum deformation at the top. Then, the pressure term of the simulation results was transferred to the Ansys solver for finite element structural analysis to observe the stresses and strains of the structure under the action of fluids. Finally, the response signal is based on Variational Mode Decomposition (VMD). Its periodic signal corresponded to the flow field, and its components were analyzed in detail. The application of VMD in this area provides innovative inspiration for related fields.

ITER ECH&CD Transmission Line Layout Development

A primary contributor to the effectiveness of the ITER electron cyclotron (EC) heating & current drive (H&CD) transmission line (TL) is the distortion of the waveguide which has a strong, direct correlation with power transmission efficiency and electromagnetic mode purity. Two main sources of distortion are the deflection of the TL due to operational loads and misalignment of the waveguide supports. To address these and other interdependent variables, the EC TL design focused on a holistic method to provide iterative simultaneous development of the system and microwave components. The process provided close, rapid interconnectivity between the prescribed subsystem requirements and the design activities being performed, including a detailed 3D configuration management model, a system structural finite element analysis, a thorough multi-sample Monte-Carlo system functional performance assessment, and individual microwave component designs & analyses. This paper intends to provide an overview of the first of these: the design development process of the TL layout. This includes investigating the inputs into layout optimization, the overall integration process, the interconnectivity with the other design activities, and their impacts on TL subsystem performance that ultimately resulted in the current baseline layout.

Stress Distribution Analysis using ANSYS of the Nose Landing Gear of STOL Aircrafts Considering Runway Gradient: A Simulation Study

Landing gear failures are a major cause of aircraft failures because they are an integral part of the aircraft's development. According to the Federal Aviation Administration (FAA), 50% of all aircraft failures occur during take-offs and landing. The landing gear of a short take-offs and landing (STOL) aircraft has had its static and dynamic forces analyzed analytically and numerically. SOLIWORKS is used to model the landing gear, and ANSYS is used to perform the numerical simulation results. Following it, the model is examined for stress and deformation with the boundary conditions and computed loads into account. This study uses structural finite element analysis (FEA) to analyze the nose gear's stress behavior and displacement during landing, as well as to assess the effect of the runway gradient. Utilizing a comprehensive numerical simulation, the landing gear of a real material Twin-Otter STOL aircraft has been demonstrated to be subjected to a dynamic force of 3653.26N, a pneumatic pressure of 1.59MPa, a bead pressure of 7.97MPa, and a vertical force of 1672.31lbs on level runways, or runways with no gradient. These findings will increase the level of confidence of aircraft manufacturers to make necessary appropriate design of STOL aircraft’s landing gear. It may can decrease the aircraft accidents and increase human life safety ultimately saving valuable time and resources too.

Finite Element Analysis of the Main Structure for a New Conceptual Aircraft Passenger Vertical Seat Design

Standing cabin is a new design concept of aircraft passenger cabin whereby passengers are transported in the standing position throughout flight as opposed to current seated position. An important element of this cabin concept is the design of the vertical seat to support the passengers, which has to be in compliance with requirements of aviation regulation. In commercial aircraft applications, weight of passenger seat is a significant factor that can affect flight performance of the aircraft. Meanwhile, the seat’s structure should have adequate strength to ensure proper safety provision to passengers. Hence weight and strength are potentially two conflicting design requirements for the vertical seat, and the optimum structural design should have the best compromise with regards to these two requirements. In this study, parametric study on primary structural design of the proposed vertical seat concept is done to obtain an optimized design that satisfies the strength requirements for safety of passengers without causing high penalty to the overall aircraft weight and performance. The simulation analysis for the main structures of the vertical seat design is conducted through finite element method using ABAQUS software. From the results of the analysis, main structural parts made from aluminium alloy with diameter 90 mm and thickness 3 mm are selected for the optimum vertical seat design. This standing seat design has also been shown to have adequate strength and can satisfy the safety regulation requirement without failure. The maximum stress on the seat’s structure under 9-g forward loading is found to be 147.5 MPa, which is lower than ultimate strength of aluminium. Moreover, the seat’s weight is estimated to be 9.5 kg and the maximum deflection of its main structures under forward 9-g loading is 28.42 mm. All in all, the stress analysis results highlight that the structural strength of the optimal vertical seat design can satisfy the requirements of the governing aviation regulations to provide safety to passengers.