Simplified FE Model Research Articles

Numerical analysis on mechanical and fatigue behaviors of aviation electrical connector considering structural effect

AbstractThis work is motivated by the fact that the reliability of electrical connectors influenced by their mechanical behavior and fatigue life directly affects the working performance of the whole equipment system. In this paper, theoretical analyses of insertion force, maximum stress, and fatigue life in an aviation electrical connector are presented and the corresponding mathematical models are firstly derived. Then, to numerically investigate its mechanical behavior and fatigue life, a simplified 3D FE model is developed by using ABAQUS and FE‐SAFE software and verified by experiments and theoretical analysis. Finally, the distribution and evolution characteristics of contact forces, stress and fatigue life considering the influences of reed thickness and slot width are quantitatively analyzed in details. The results indicate that the insertion force first increases and then stabilizes at the level of 0.16 N as the pin head is fully inserted into the jack, which shows an opposite to the evolution of extraction force. Moreover, the maximum value of stress and the minimum value of fatigue life are all located at the root of the jack reed. Besides, unlike the small effect of slot width, the Fimax and σmax values obviously increase and the Nf value decreases with the increment of reed thickness.

Analysis of PMSM NVH performance in electric propulsion systems using FE models

The stator of the PMSM is the main transfer path for the Electro Magnetic (EM) force from stator teeth to the drive unit (DU) through its mounting ears. First, a FE model of full winding stator model along with connection ring is analyzed for modal behaviors. Time domain EM force excitations are converted into frequency domain and applied at the stator teeth. This enables stator mounting forces analysis at all critical NVH orders. Next, the detailed FE modelling approach is compared with response calculated form a simplified modelling approach, with stator end windings modelled as lumped mass and inertia to reduce computational time. The comparison study of two approaches clearly shows the benefits of using simplified FE models for studying motor whine with reduced modelling and computational costs. Furthermore, the frequency-dependent stator damping measured from modal test is applied in electric DU analysis to evaluate NVH performance excited by motor EM force excitations using simplified stator model. The sound power level radiated from the DU and the mount vibration response show negligible influence of stator damping at DU unit level NVH response in the low frequency range. Analysis and test results correlate reasonably well at the dominant motor whine orders for the DU, which validates the proposed method.

A new biomechanical FE model for blunt thoracic impact.

In the field of biomechanics, numerical procedures can be used to understand complex phenomena that cannot be analyzed with experimental setups. The use of experimental data from human cadavers can present ethical issues that can be avoided by utilizing biofidelic models. Biofidelic models have been shown to have far-reaching benefits, particularly in evaluating the effectiveness of protective devices such as body armors. For instance, numerical twins coupled with a biomechanical model can be used to assess the efficacy of protective devices against intense external forces. Similarly, the use of human body surrogates in experimental studies has allowed for biomechanical studies, as demonstrated by the development of crash test dummies that are commonly used in automotive testing. This study proposes using numerical procedures and simplifying the structure of an existing biofidelic FE model of the human thorax as a preliminary step in building a physical surrogate. A reverse engineering method was used to ensure the use of manufacturable materials, which resulted in a FE model called SurHUByx FEM (Surrogate HUByx Finite Element Model, with HUByx being the original thorax FE model developed previously). This new simplified model was validated against existing experimental data on cadavers in the context of ballistic impact. SurHUByx FEM, with its new material properties of manufacturable materials, demonstrated consistent behavior with the corresponding biomechanical corridors derived from these experiments. The validation process of this new simplified FE model yielded satisfactory results and is the first step towards the development of its physical twin using manufacturable materials.

Superelasticity SMA cables and its simplified FE model

Superelasticity SMA cables and its simplified FE model

Seismic Performance of a Hybrid Coupled Wall System Using different Coupling Beam Arrangements

This study implemented multirecord nonlinear dynamic and fragility analysis in order to gain more insight into the hybrid coupled wall (HCW) system. Two potentials are used to construct coupling beams, which are the typical steel coupling beam and the replaceable steel coupling beam. Furthermore, an innovative idea for replaceable beams is discussed utilizing reinforced concrete infill instead of steel stiffeners. A new simplified FE model for such beam is carried out in order to explore how this new beam influences the seismic performance of HCW system. An additional equivalent bare RC wall case study is also taken into account for a comprehensive comparison. A precise 2D modelling method using Opensees platform is adopted after validation against experimental and complex 3D numerical simulations. The results indicate a good effect of the replaceable coupling beams concept upon reducing the vulnerability of wall piers under low and moderate events. In terms of coupling beams fragility, the replaceable steel coupling beams also demonstrate better damage resistance when compared with typical steel beams under low and moderate seismic events. Using reinforced concrete infill instead of steel stiffeners can significantly protect beams maintenance without affecting wall piers’ vulnerability.

Study on withdrawal load resistance of screw in wood-based materials: experimental and numerical

ABSTRACT The effects of screw diameter, pilot hole, and material type on withdrawal load resistance (WLR) of screw driven in medium density fibreboard (MDF) and particleboard (PB) were investigated through using experimental and numerical methods. Meanwhile, the results of experimental tests and numerical analysis were compared with the empirical equations. The results showed that (1) the material type and the diameter of screw had significant effects on the WLR, but the pilot hole was not; (2) the equations proposed in Eurocode 5 had better performance in predicting WLRs of screw in both MDF and PB than the other equations; (3) density distributions of wood-based materials affected the mechanical behaviours of WLR of screw; (4) finite element model (FE-model) established could be used to simulate the WLR of screw in wood-based samples; (5) the complex FE-model considering threads of screw can reflect the stress distributions on threads in detail, which contributes to optimal design of threads geometry of screws. And the simplified FE-model without considering threads of screw had advantages in predicting the WLR with higher accuracy.

Simplified Fe Model and Experimental Study on the Tensile Properties of the Glass Fiber Reinforced Polyester Polymer

Simplified Fe Model and Experimental Study on the Tensile Properties of the Glass Fiber Reinforced Polyester Polymer

Optimization for friction damped post-tensioned steel frame based on simplified FE model and GA

Optimization for friction damped post-tensioned steel frame based on simplified FE model and GA

Applications of simplified 3D FE model in seismic analysis for friction-damped posttensioned steel frame structures

The post-tensioned (PT), energy-dissipating connection for steel frames has drawn the attention of many researchers due to its role in ensuring a favorable seismic performance. The energy-dissipating capacity of these frames is often improved by various friction mechanisms, such as friction-damped PT (FDPT) steel connections. Numerous researchers have investigated the seismic behavior of FDPT by using either the numerical or experimental method. However, previous studies have mostly relied on elaborate, time-consuming FE models, and analyzing a 3D frame structure is nearly impossible. To overcome these limitations, this paper proposed and analyzed a mechanical model of 3D FDPT as well as a 3D FE model of FDPT frame structures. The seismic responses of traditional and FDPT frame structures were also analyzed and compared. The results provide a foundation for the future analysis and design of PT frame structures.

Influence of different topological variants on optimized structural scantlings of passenger ship

For a multi-deck ships with extensive superstructures (such as passenger and cruise ships, RoPax, mega yachts, etc.) the global structural response can be particularly complex. The influence of the superstructure to the primary strength for those multi-deck ships must be considered from an early design phase. Main global topological parameters (e.g. size of side openings, position and stiffness of longitudinal and transverse bulkheads, etc.) have dominant influence on the shape of hull girder stress distributions over the ship height. The Taguchi concepts and techniques (FFE, orthogonal arrays, ANOVA, etc.) could be used to systematically study influence of multiple topological parameters on the global structural response obtained by FEM analysis. It also enables rational identification of the most dominant parameters and provide designer with the near-optimal level of each topological parameter for the defined design objective. It has been demonstrated how different topological variants can lead to different optimal structural scantlings w. r.t chosen design objectives (mass, VCG, etc.), using simplified full ship 3D FE model of passenger ship as an example. Structural design software MAESTRO and in-house developed framework for the design support system DeMak – OCTOPUS Designer were used as a structural optimization tool. This paper aim to extend the standard scantling optimization by introducing topological aspects as a first STEP in overall optimization procedure.

A new and lean finite element model to predict the out of plane crash behaviour of aluminium honeycomb structures

Aluminium honeycombs are well-known anisotropic structures which are commonly used as energy absorber units. In the past decades, several researchers have focused on developing finite element models credible enough to predict the crash behaviour of honeycomb structures. A number of modelling methodologies have been developed and validated to closely represent the structural behaviour under various boundary conditions. Due to the limitations with modelling the structure accurately as well as the adhesive failure and trapped air, presents a serious challenge to predict the crushing behaviour of honeycomb structures. This paper introduces multiple simplified FE models and the results from simulations are compared with experimental data to evaluate the most effective model. The results have also been compared with our existing article which used LSDYNA for numerical analysis. The techniques proposed in this paper show good correlation with the mentioned experimental data and the LSDYNA model. Thus, the simplified FE models are regarded as validated and credible enough to predict out-of-plane crash behaviour of aluminium honeycomb. Altair’s HyperMesh and HyperCrash were used to create the FE models and the dynamic explicit code RADIOSS to solve the models.

An Improved Method for Dynamic Behaviour Prediction of Carbon Fibre Reinforced Epoxy (CFRE) using Finite Element Model Updating

The dynamic behaviour prediction scheme of carbon fibre composite structures are extremely challenging to be performed due to the geometrical ply-by-ply properties and the ply orientation issues. In this paper, a laminated carbon fibre reinforced epoxy plate with elastic and linear layers was used with aim to investigate the dynamic behaviour of the carbon fibre reinforced epoxy using practical modelling scheme via finite element modelling and updating method. A simplified FE model of the CFRE plate was developed using shell element properties known as PSHELL to represent geometrical laminated properties. Subsequently, the dynamic behaviour of the FE model was calculated using Nastran SOL103. Potential updating parameters of the FE model was analysed and identified using the sensitivity analysis. The model updating method was then used to update the initial FE model of the CFRE plate based on the experimental modal analysis (EMA) result. The comparison of the results were used in verifying the accuracy of the updated FE model of the CFRE plate. The result suggested that the PSHELL properties can be used efficiently to represent the geometrical laminated properties of the CFRE plate without considering the geometrical effect of ply-by-ply properties.

BVS stent optimisation based on a parametric model with a multistage validation process

Developing new polymer-based bioresorbable vascular scaffolds (BVS) requires a new structural geometry, as these polymer materials are characterised by substantially lower stiffness than metallic alloys. Sufficient radial strength of the stent is essential, as insufficient vessel wall support can lead to a significant recoil (reduction of the vessel lumen) and can cause dangerous complications. To assess the stress development and deformation of the stent, finite element analysis (FEA) was used. First, a complex FEA of the inflation and crimping processes of a bioresorbable coronary stent was performed. An optimisation procedure based on the simplified parametric FE model was subsequently performed to obtain the optimal geometric parameters of the analysed structure. The objective of the optimisation was to maximise the vessel diameter after the BVS implantation. The optimisation procedure was based on automatic model-generating scripts, numerical analyses and implementation of genetic algorithms. Finally, a comparison of the parametric and complex models results was performed, as well as a final validation at several stages (structural studies, computational fluid dynamics (CFD) simulations and in vivo testing). The validation confirmed that the presented optimisation methodology represents a valid and useful tool for the stent design process.

Influence of forging velocity on temperature and phase transformation characteristics of forged Ti-6Al-4V aeroengine drum

This study is prompted by the reality that the forging velocity greatly impacts the phase transformation of titanium forged parts, further affecting the ultimate microstructures and mechanical properties of their final parts. In this paper, to predict the transformation characteristics of temperature and phases in Ti-6Al-4V drum hot forging procedure, a simplified FE model embedded with phase transformation equations is developed and verified by experiments. Then, based on two evaluation indexes, the effect of forging velocity on the transformation characteristics of temperature and phases within the forged drum is analyzed quantitatively. The results suggest that unlike little effect on lamellar α+β phase, appropriately enhancing the forging velocity can increase the general levels of temperature and β phase and improve the uniformities of temperature, α phase, and β phase distributions within the forged drum.

Research for Estimation of Heat Source Model Parameters with Simplified FE Model & Global Optimization Algorithm Part I. Application of Adaptive Simulated Annealing

Research for Estimation of Heat Source Model Parameters with Simplified FE Model & Global Optimization Algorithm Part I. Application of Adaptive Simulated Annealing

Modal Velocity-Based Multiaxial Fatigue Damage Evaluation Using Simplified Finite Element Models

Abstract This work proposes a new method for the fatigue damage evaluation of vibrational loads, based on preceding investigations on the relationship between stresses and modal velocities. As a first step, the influence of the geometry on the particular relationship is studied. Therefore, an analytic expression for Euler Bernoulli beams with a non-constant cross section is derived. Afterward, a general method for obtaining geometric factors from finite element (FE) models is proposed. In order to ensure a fast fatigue damage evaluation, strongly simplified FE-models are used for the determination of both factors and measurement locations. The entire method is demonstrated on three mechanical structures and indicates a better compromise between effort and accuracy than existing methods. For all examples, the usage of velocities and geometric factors obtained from simplified FE models enables a sufficient fatigue damage calculation.

Fracture response of resistance spot welded dual phase steel sheets: Experiments and modeling

Predicting the failure of spot welds remains one of the most important modeling challenges in automotive engineering. In essence, the structure surrounding a spot weld corresponds to a graded material with severe variations in the plasticity and fracture properties as a function of the distance to the center of the weld nugget. While it is common practice to identify hardness variations around a spot weld, a newly developed micro-tensile testing technique is used to characterize spatial variations in both strain hardening and fracture strains. Furthermore, a new experimental device is presented to subject spot welds to combined tension, shear and bending loads. Following a careful experimental characterization of resistance spot welds connecting two 1.5 mm thick DP600 sheets, a detailed finite element model is built which accounts for the identified property gradients. In addition, a simplified surrogate model for use in conjunction with coarse shell element meshes is also calibrated. Simulations are performed of all structural experiments to assess the range of validity of the detailed and simplified FE models. It is found that the detailed model captures the experimentally observed failure modes including changes in the location of fracture initiation as a function of the loading, while the simplified model is able to predict the spot weld strength with reasonable accuracy.

Influence of design parameters on bending piezoelectric harvester effectiveness: Static approach

In the presented paper the considered energy harvester is a cantilever beam consisting of a non-piezoelectric substructure layer covered symmetrically on its both sides with two identical piezoelectric layers. At this stage of the study a quasi-static load is considered and realized by the beam tip deflection.Two types of modeling and calculations are proposed i.e. the analytical method in which the effective electromechanical coupling coefficient is taking into account and the finite element method (FEM) in which the mechanical and electrical energies are numerically calculated. The main goal of the study is to show the influence of design parameters like stiffness ratio and thickness ratio of the piezoelectric and substructure layers on the harvester effectiveness. It is shown that the applied two different evaluations of the energy conversion give the optimal, in energy point of view, geometrical and material properties in quite good agreement. The obtained results confirm correctness of the proposed two-dimensional FE model.Using this simplified FE model, the optimal length of the piezoelectric layers in relation to the layer stiffness ratio is also indicated for two specified values of the thickness ratios.

Application of efficient TEP FE computation on accurate fabrication of cylindrical leg structure of jack-up rig

Cylindrical leg structure is an essential component of jack-up rig, and its fabrication accuracy will significantly influence the operation performance and service lift. Due to the welding distortion generated during rack and cylinder joining and its effect on dimensional profile of cylindrical leg structure, the experiment to fabricate the cylindrical leg structure and dimensional measurement were conducted in advance, and highly efficient Thermal Elastic Plastic (TEP) FE computation with Iterative Substructure Method (ISM) and OpenMP parallel computation was proposed and employed for welding distortion prediction. Simplified cylinder FE model was considered to clarify the mechanism of dimensional variation in advance, and efficiency of proposed TEP FE computation was also demonstrated. Quarter FE model of rack and cylinder welded structure was then employed due to its symmetrical feature while computed results have a good agreement comparing to the measurement. Meanwhile, in order to improve the fabrication accuracy, bead-on-plate welding on inner surface of cylindrical leg structure was numerically examined, while inverse deformation can be generated and has significant influence to mitigate welding distortion during rack and cylinder joining.

Assessment of fretting fatigue in high strength steel bolted connections with simplified Fe modelling techniques

Abstract The fretting fatigue (FF) damage on contact surfaces constitutes a major problem in High Strength Steel (HSS) bolted connections when subjected to cyclic loadings, in that it significantly lowers the fatigue life. Moreover, the estimation of damage in the contact areas is challenging and laborious through experiments. The present paper proposes a simplified modelling technique to estimate the fretting fatigue damage in high cycle regime by considering the pretension effect and contact properties of bolted lap connections. To do so, a three-dimensional solid model is developed and validated. Afterwards, simplified FE models are validated using the three-dimensional model and test results to identify the most computationally efficient model for bolt connection in HSS under static and fatigue loading conditions. It was observed that the newly developed FE model could retain all the components on contacting surfaces while saving of up to 97% of the computational time over full solid models. These results successively provided insight into the crack initiation location and the fatigue lifetime of the joint and showed good agreement with experimental and three-dimensional solid model data.