Finite Element Structural Analysis Research Articles

Development of a tiny house design tool to increase safety, efficiency, and cost-effectiveness

The popularity of tiny houses is increasing, but the technical details are rarely covered. Therefore, this study examines the structural, stability, weight, and thermal requirements of tiny houses. A configurable SolidWorks model was created, and the location and quantity of structural supports were determined by performing structural finite element analyses (FEA). The center of mass, tip angles, overall weight, and tongue weight were computed to ensure stability while stationary or during transit. The heating and cooling needs for the tiny houses were calculated using thermal FEA for twelve cities of varying climates across the United States.The result was a Scilab design tool that takes as input, items such as location, desired size, utility needs, etc. It calculates the materials needed for the structure and the projected cost. This design tool, along with the provided construction drawings, allows the user to build a safer, efficient, and cost-effective tiny house.

Prediction of the mechanical response of a 3D (bio)printed hybrid scaffold for improving bone tissue regeneration by structural finite element analysis

Scaffolds for bone tissue engineering should be osteoinductive, osteoconductive, biocompatible, biodegradable, and, at the same time, exhibit proper mechanical properties.The present study investigated the mechanical properties of a coprinted hybrid scaffold made of polycaprolactone (PCL) and an alginate-based hydrogel, which was conceived to possess a double function of in vivo bio-integration (due to the ability of the hydrogel to release lyosecretome, a freeze-dried formulation of mesenchymal stem cell secretome with osteoinductive and osteoconductive properties) and withstanding loads (due to the presence of polycaprolactone, which provides mechanical resistance).To this end, an in-silico study was conducted to predict mechanical properties. Structural finite element analysis (FEA) of the hybrid scaffold under compression was performed to compare the numerical results with the corresponding experimental data. The impact of alginate inclusion and infill patterns on scaffold stiffness was investigated.Results show an increase in mechanical properties by changing the scaffold infill pattern (linear: 145.38±28.90 vs. honeycomb: 278.96±50.19, mean and standard deviation, n = 8), while alginate inclusion does not always impact the mechanical performance of the hybrid scaffold (stiffness: 145.38±28.90 vs. 195.42±38.68 N/mm, with vs without hydrogel inclusion, respectively). This is confirmed by FEA analysis, in which a good correspondence between experimental and numerical stiffness is shown (142±28.94 vs. 117.18, respectively, linear scaffold with hydrogel inclusion).In conclusion, the computational framework is a valid tool for predicting the mechanical performance of scaffolds and is promising for future clinical applications in the maxillofacial field.

Investigating the effects of shroud and blade thickness profiles on aeromechanical behavior and fatigue-life of 17-4PH impellers

In the present study, effects of blade and shroud thickness profiles on the stress distribution and fatigue life of centrifugal compressor impellers are investigated. Impeller geometry is generated based on an available data of a single-stage centrifugal compressor and is simulated in actual operating conditions. Pressure distribution on the impeller blades is obtained using Computational Fluid Dynamics (CFD) simulation which is then incorporated into Finite Element (FE) structural analysis. Equivalent stress and total deformation contours on the impeller are employed to pinpoint critical areas and maximum stress values. Simulations are performed for multiple cases with various shroud and blade thickness values to capture the role of these important parameters in aeromechanical behavior of the structure. Furthermore, fatigue stress amplitude limit and fatigue-life are evaluated based on the results of the FE analyses. It will be demonstrated that semi-open configuration is the most desirable design from mechanical stress and fatigue-life viewpoints. For shrouded impellers, it is shown that the mechanical stress increases and fatigue life decreases with increasing the blade thickness while for the shroud thickness, there exist an optimal point with minimum stress level and maximum fatigue life. The methodology and results of this paper can be employed for other impellers with different geometries and operating conditions to find the optimal design points from the structural mechanics perspective.

Design and Analysis of UAV Test Bench for Engine/Motor Characterization

A thrust test bench is an instrument which can measure the Thrust, Rpm, Power, Torque, Temperature Explicitly etc. This is composed of the test bench architecture attached to the motor or the engine through the rotating shaft. An absorber being attached to the engine means nothing but an extra component which drives the energy of the motor, that is a propeller if assumed. The main objective here is to design a Test Bench which can maximum hold the weight of UAV Engines or motors within 15kgs and to conduct Structural Finite Element Analysis on different parts of the test bench to determine the stress behaviour. The parameters which the test bench can measure are Thrust, Velocity, Rotational Speed, Torque, Cylinder Head Temperature, Exhaust Temperature etc. This is achieved by using certain sensors introduced with a DAQ system for precise and accurate measurements of the parameters.

Challenges in GPU-Accelerated Nonlinear Dynamic Analysis for Structural Systems

Many numerical simulation methods, such as finite-element analysis, were originally formulated to run serially or in parallel on central processing units (CPUs). However, computer engineering has seen a paradigm shift toward massive parallelism using graphics processing units (GPUs), which have become the default accelerators in many data-driven scientific disciplines outside of civil engineering. This state-of-the-art review highlights the challenges and practicalities of GPU-accelerating nonlinear dynamic analyses for civil structural problems. To demonstrate the feasibility of a fully GPU-accelerated finite-element analysis, a GPU-based program for linear-elastic dynamic analysis was implemented, where all stages of the analysis were ported to the GPU. Observed speedups were 115 times that of an equivalent CPU-driven analysis for 106 model degrees of freedom (dof). Importantly, the computational time for the assembly and update levels of the analyses were nearly independent of the number of dof. High-resolution simulations of complex structures can be computationally expensive, but these results and advances in other fields suggest that some levels of the finite-element analysis of civil structures could be accelerated using GPUs at increased model resolution with little increase in computational cost, demonstrating the potential for GPU-accelerated computing. However, compared to other GPU-accelerated finite-element analysis applications, the dynamic analysis of civil structures is subject to unique challenges that need to be addressed before GPU acceleration can be fully realized. Aspects of simulating the response of civil structures considering nonlinear response under extreme loading may not be immediately amenable to GPU acceleration; e.g., the use of many differing element formulations within a model, potential for inelastic response and varying degrees of nonlinearity across elements, and traditional reliance on implicit integration schemes with direct solvers. The shift to GPUs is part of a larger movement toward specialized hardware using fine-grained parallelism, and structural engineers need to address these challenges as these emerging technologies become more prevalent.

Topology Optimization Framework for Simultaneously Determining the Optimal Structural Design and Current Phase Angle of the IPMSMs for the MTPA Control

Although it is crucial to design the magnetic flux path and the maximum torque per ampere (MTPA) current reference under the current limitation, it is challenging to simultaneously consider these features in developing an interior permanent magnet synchronous motors (IPMSM) due to complicated coupling effects. In this article, to overcome the above issue, the motor-design parameters are estimated by conducting electromagnetic finite element (FE) analysis two times at every iteration of topology optimization. Then, the MTPA current phase angle can be analytically expressed in terms of an elementwise relative density (i.e., design variable in topology optimization). In addition, the structural safety is assessed by conducting the structural FE analysis under design-dependent loads to reflect a high-speed rotation. The proposed two-stage topology optimization enables us to simultaneously optimize both a structural design and current phase angle to achieve the maximum electromagnetic performance. Structural safety and manufacturability are also considered to obtain a practically meaningful design. With two different types of permanent magnets, the optimized IPMSMs are obtained and manufactured to validate the proposed method. Simulation and experimental results demonstrate the validity and potential of this work.

The engineering design of half-size RF negative ion source for CRAFT-NNBI

The full-size radio frequency (RF) negative ion source used in comprehensive research facility for fusion technology (CRAFT) has four drivers, which are arranged in the vertical direction. In order to study the physical and engineering issues, a quarter-size negative ion source was designed, developed and tested in ASIPP. This source has only one driver, making it impossible to research radio frequency interference and large-area plasma uniformity when multiple drivers work together. Therefore, a half-size negative ion source with dual drivers is developed in this study. The half-size negative ion source with dual drivers has been successfully developed and used as a module. Two half-size negative ion sources were assembled after the improvement to complete the overall design of the full-size negative ion source, which is of great significance to the entire beam source project. This paper mainly introduced the structural design, structural finite element analysis and key component manufacturing process test of the half-size negative ion source.

A Finite Element Analysis of Bottom Structure of LCT Converted from SPOB

SPOB (Self-Propelled Oil Barge) ship is useful for transporting oil. Due to certain requests, the owner and operator have converted SPOB into LCT. If before the conversion the ship transported oil, now the ship is transporting vehicles or heavy equipment on the deck. after the transfer of function from a SPOB ship to an LCT (Landing Craft Tank) ship, the cargo transported is different, the bottom is the part that is submerged in the water, so this part is vulnerable. Therefore, it is necessary to systematically predict the weight of the load that can be held by the ship at the bottom, this is so that there is no damage to the structure at the bottom of the ship which can harm the company from the ship owner. The purpose of this study is to find the maximum stress and strain that can be accepted by the ship and the value of the stress ratio (safety factor) in the bottom construction using the finite element method. The results obtained from the maximum stress and strain of the ship after and before conversion of 96.349Mpa, 272.56 Mpa, and 0.0013628 mm, 5.042 x 10-4 mm, safety factor according to BKI after and before conversion obtained 3.624 and 1.057, the safety factor according to the material criteria is 3.685 and 1.172, respectively, for the maximum deformation of the ship, the safety factor is 6.328 and 3.287 respectively

An Integrated Design Study for an Advanced Tokamak to Close Physics Gaps in Energy Confinement and Power Exhaust

A high-level design study for a new experimental tokamak shows that advances in fusion science and engineering can be leveraged to narrow the gaps in energy confinement and exhaust power handling that remain between present devices and a future fusion pilot plant (FPP). This potential new U.S. facility, an Exhaust and Confinement Integration Tokamak Experiment (EXCITE), will access an operational space close to the projected FPP performance regime via a compact, high-field, high-power-density approach that utilizes advanced tokamak scenarios and high-temperature superconductor magnets. Full-device optimization via system code calculations, physics-based core-edge modeling, plasma control simulations, and finite element structural and thermal analysis has converged on a T, MA, m, , D-D tokamak with strong plasma shaping, long-legged divertors, and 50 MW of auxiliary power. Such a device will match several absolute FPP parameters: plasma pressure, exhaust heat flux, and toroidal magnetic field. It will also narrow or close the gap in key dimensionless parameters: toroidal beta, bootstrap fraction, collisionality, and edge neutral opacity. Integrated neutron shielding preserves personnel access by limiting nuclear activation and maximizes experimental run time by reducing site radiation. In addition to design study results and optimization details, parameter sensitivities and uncertainties are also discussed.

Progressive bridge collapse analysis under both scour and floods by coupling simulation in structural and hydraulic fields. Part Ⅰ: Numerical solver

Hydraulic bridge failures have become the greatest threat to the structural safety of bridges. Combined numerical simulations are rare due to the high computational cost of structural nonlinear finite element analysis (NLFEA) and computing fluid dynamics (CFD). Structural analysis and design for extreme hydrological hazards are challenging due to complicated hydrodynamics-soil-structure interactions. This paper proposes a numerical solver to simulate hydraulic bridge failures through coupling simulations. The solver applies hydrodynamic load and updates scour boundary in a structural model by utilizing a scatter linear interpolation method based on the Delaunay triangulation algorithm in each loop solution. Then, a simplified sediment stress model considering external forces in the vertical plane and a complex model with an arbitrary slope in three-dimensional coordinates are introduced into the basic incipient motion model of sediment, resulting in a more realistic stress state of sediment. Finally, the numerical solver is adapted to provide an accessible method to investigate the influence of such a modified model on the scour process and structure response. Meanwhile, the validation of this numerical solver is conducted in a companion paper based on the comparison between the numerical result of the hybrid model and the field data.

HCF and LCF Analysis of a Generic Full Admission Turbine Blade

A numerical turbine-blade fatigue-life analysis method is suggested. This method comprises a stationary thermal 3D finite element (FE) analysis of the hot run for the combined high-cycle fatigue (HCF) and creep analysis, and a follow-on (one-way coupled) quasi-stationary structural 3D FE analysis (including six load steps) of a single and two half turbine blades and the related disk and rotor section and a (modified Goodman equation based) post-processing fatigue life analysis for the highest HCF-loaded point of the turbine blade. For the low-cycle fatigue (LCF) analysis, this includes a transient thermal 3D FE analysis of two full loading cycles, a follow-on (one-way coupled) quasi-stationary structural 3D finite element analysis of a single and two half turbine blades and the related disk and rotor section and a (modified-Langer-equation-based) post-processing fatigue life analysis approach for the highest LCF-loaded point of the turbine blade. Finally, this approach is demonstrated by the numerical HCF, LCF and creep analysis of a generic turbine blade of the first rotor row of a full admission hydrogen turbo pump of a 1 MN thrust class gas generator LOX-LH2 liquid rocket engine (LRE). For this numerical example, the LCF loading turned out to be dominant. Creep turned out to be negligible.

Balancing domain decomposition method for large-scale analysis of an assembly structure having millions of multipoint constraints

A method by which to incorporate multipoint constraints (MPCs) into the balancing domain decomposition (BDD) method proposed in a previous study (BDD-MPC method) is investigated, improved, and applied to realistic and complex problems. First, the effects of the penalty term to take into account the MPCs in the coarse-grid problem of the BDD method are investigated. Then, improved implementation techniques for the BDD-MPC method are proposed. The computation speed of the projection procedure in the conjugate projected gradient method is improved using the block diagonal structure of the constraint matrix. The parallel solution procedure for the coarse-grid problem considering the MPCs that are projected to the coarse space is also improved. The improved MPC-BDD method is implemented in ADVENTURE_Solid, which is a parallel finite element structural analysis code. The code is parallelized using an MPI-OpenMP hybrid parallel implementation framework. In the previous study, the BDD-MPC method was applied to only simple numerical examples. In the present study the performance of the improved method is demonstrated by solving super-high-rise building models having very complex geometry and several million MPCs.

The asymptotic concentration approach combined with isogeometric analysis for topology optimization of two-dimensional linear elasticity structures

<abstract> <p>We propose an asymptotic concentration approach combined with isogeometric analysis (IGA) for the topology optimization of two-dimensional (2D) linear elasticity structures under the commonly-used framework of the solid isotropic materials and penalty (SIMP) model. Based on the SIMP framework, the B-splines are used as basis functions to describe geometric model in structural finite element analysis, which closely combines geometric modeling with structural analysis. Isogeometric analysis is utilized to define the geometric characteristics of the 2D linear elasticity structures, which can greatly improve the calculation accuracy. In addition, to eliminate the gray-scale intervals usually caused by the intermediate density in the SIMP approach, we utilize the asymptotic concentration method to concentrate the intermediate density values on either 0 or 1 gradually. Consequently, the intermediate densities representing gray-scale intervals in topology optimization results are sufficiently eliminated by virtue of the asymptotic concentration method. The effectiveness and applicability of the proposed method are illustrated by several typical examples.</p> </abstract>

Topology Optimization for the Manufacturable and Structurally Safe Synchronous Reluctance Motors With Multiple Iron Webs and Bridges

The goal of this article is to develop a new topology optimization framework that can secure the manufacturability of the synchronous reluctance motors (SynRMs) with multiple iron webs and bridges while satisfying the required electromagnetic and mechanical performances. In the SynRM, multiple iron webs and bridges are crucial to achieve a higher torque and a structural safety. A minimum thickness of the web and bridge should also be guaranteed to achieve manufacturability. To acquire the optimal SynRM that can satisfy the above characteristics, a two-stage topology optimization framework is proposed with an individual filtering-and-penalization scheme. This proposed scheme can individually control the number and thickness of multiple iron webs and bridges in the rotor to obtain the manufacturable and structurally safe SynRMs. For the abovementioned purpose, topology optimization is formulated to minimize a torque ripple while satisfying the desired average torque, structural compliance, and a rotational moment of inertia. Average torque and structural compliance are evaluated by performing the electromagnetic and structural finite element analyses, respectively, at each iteration of topology optimization. Here, design-dependent loads are considered in the radial and circumferential directions to reflect a high-speed rotation. Through investigating the optimized SynRM designs with various filter radii, the relationship among the torque, structural pattern, and stress distribution is examined. Finally, the experimental results with the manufactured prototypes validate the feasibility and potential of the proposed design method.

Adaptive mesh refinements for analyses of 2D linear elasticity problems using the Kriging-based finite element method

Finite element analyses of irregular structures require adaptive mesh refinement to achieve more accurate results in an efficient manner. This is also true for a non-conventional finite element method with Kriging interpolation, called the Kriging-based finite element method (K-FEM). This paper presents a study of automatic adaptive meshing procedures for analyses of two-dimensional linear elasticity problems using the K-FEM. The Matlab Partial Differential Equation Toolbox was utilized for generating meshes with Delaunay triangulation. Three error indicators, namely, the strain energy error, the gradient of effective stresses, and the element-free Galerkin strain energy error, were employed for estimating the element errors. To find the most effective error indicator, the resulting total number of elements and configurations of the final meshes were compared. The results show that the resulting final meshes were affected by the initial mesh configurations, the refinement criteria, and the termination criteria. The gradient of effective stresses indicator was found to be the most effective error indicator for the K-FEM, as it can accurately estimate the element errors.

Structural Design and Finite Element Analysis of a Heavy Equipment Shelter

Structural Design and Finite Element Analysis of a Heavy Equipment Shelter

Shear behavior of ultra-high-performance reinforced concrete beams – Finite element and uncertainty quantification study

This study examines the safety and the model uncertainty of the ACI 318, ACI-PRC 239/ACI 544, and JSCE/KCI design codes in terms of their shear strength model for UHPC beams. Structural reliability and finite element analyses were employed to achieve this objective. The FE model developed in this study could accurately predict the shear behavior of nine UHPC beams selected from three different previous kinds of research tested up to their failure loads. The numerical model provided a mean test-to-prediction value of 99.4% with a coefficient of variance of 2.3%. Moreover, the design models for ACI 318 and ACI-PRC 239/ACI 544 consistently underestimated the shear capacity of UHPC beams. For these design codes, the predicted-to-tested values ranged from 1.4 to 12.8 and 1.1 to 5.7, respectively. In comparison with the ACI 318 code, the ACI-PRC 239/ACI 544 model had less variability and produced more accurate results. The JSCE/KCI model predicted the UHPC shear capacity of the UHPC beams more precisely than the ACI models, showing an observed-to-calculated mean value of 1.49. The reason for this superiority was attributed to consideration of the JSCE/KCI model for the fiber–matrix interactions of the UHPC. Using ACI 318 and ACI-PRC 239/ACI 544, it was expected that the relevant reliability indices would have relative values. However, these design codes yielded an index of reliability for the shear strength of UHPC beams that was slightly below the target value of 4.15, thereby presenting a safety issue. However, it was expected that greater safety could be achieved using the JSCE/KCI.

Efficient stress integration algorithm of memory surface model with shrinking rule under plane stress field

Reliable nonlinear finite element analysis (FEA) of steel structures requires a constitutive model capable of predicting the cyclic plasticity of structural steels. Steel structure members are typically composed of multiple thin steel plates. The FEA of such structures has frequently used shell elements to capture the bending deformation and reduce the computational complexity, where its stress state can be regarded as the plane stress field. This study provides a constitutive model with a memory surface under a plane stress field for the cyclic plasticity of structural steels. A noble computationally efficient algorithm for stress integration and consistent tangent operator was proposed, where the constitutive equations were linearized after solving some unknown variables. The proposed model was implemented in the Abaqus FEA code. The residual-force convergence rate of the consistent tangent operator is investigated using a single-shell element under simple boundary conditions, where the consistent tangent operator achieves more than a quadratic convergence. The proposed model was validated by comparing the experimental results and FEA results with the proposed model for thin-walled steel members under cyclic loading. The average difference in peak forces between FEA and experimental results was 11.5 % for the local buckling tests and 8.4 % for the shear buckling tests at most. These results suggest that the proposed model provides an accurate prediction for other thin-walled steel structures under cyclic loading.

A framework for plasticity‐based topology optimization of continuum structures

AbstractIn this paper, a framework is proposed for topology optimization of continuum structures considering plasticity. The method merges the rigid‐plastic analysis and the density‐based topology optimization. To obtain a clean black‐and‐white design, the density in the objective function is penalized using an exponential function. The solution of the final plasticity‐based topology optimization problem exhibits as a sequence of second‐order cone programming (SOCP) problems that can be resolved efficiently using the advanced primal‐dual interior point method. Compared to the conventional stress‐constrained topology optimization techniques, the developed method accounts for plasticity and the finite element analysis of structures does not need to be carried out separately. Furthermore, the proposed method requires no relaxation techniques for imposing local stress‐constrain and possesses good computational efficiency for large‐scale problems.

Finite Element Analysis and optimization design of sprinkler Truss Structure

This paper includes three sections. Truss structures have been widely applied in bridges and buildings due to their light weight, reasonable load-bearing, and high material utilization rate. For truss structures serving as load-bearing carriers, their structural strength should be guaranteed, and moreover, their economic performance should be considered. First, the finite element theory was introduced, and the computer-aided simulation analysis was performed by combining numerical analysis and finite element theory. Second, the truss structure of a sprinkler was subjected to a mechanical analysis, and its stability was explored with its maximum displacement and maximum stress as constraints. Finally, the truss structure was optimally designed until its stability, strength, and stiffness met relevant requirements.