Finite Element Model For Evaluation Research Articles

Hysteresis finite element model for evaluation of cyclic behavior and performance of steel plate shear walls (SPSWs)

Evaluation of hysteresis behavior and ultimate capacity of steel plate shear walls (SPSWs) with complex geometry and details, using the equivalent constitutive models infill steel plate, is known as a complex process. Therefore, using a simplified micro-finite element (MFE) model is necessary in evaluation of the hysteresis behavior and performance of the SPSW with different construction details. The proposed MFE model was performed in microscopic analysis models for web-plates and boundary members. To this end, comprehensive verification studies are initially performed by assessment of between the MFE model predictions with several reported test results in order to demonstrate the reliability and accuracy of the implicit analysis method. Comparison is made between the hysteresis curves, failure modes, and base shear capacities predicted numerically using ABAQUS software and obtained/observed experimentally. The results of this analysis exhibit that the proposed MFE model can evaluate the hysteresis behaviour and failure mode of SPSW structures with any type of geometric and materials properties. Meanwhile, this proposed model was implemented so that designers are capable to comfortably using the proposed model with good computational accuracy and efficiency.

Simplified finite element model for evaluation of ultimate capacity of corrosion-damaged reinforced concrete beam-columns

A simplified nonlinear finite element analysis (NLFEA) based on enhanced inspection, material testing, and nonlinear sectional analysis is introduced as part of a semi-quantitative assessment approach of aged beam-columns. The focus is on the evaluation of the structural performance and residual capacities of slab-on-girder bridge columns subjected to combined external loads and reinforcement corrosion. NLFEA takes into account different levels of geometrical, material, and bond damage due to reinforcement corrosion. At each load step of the nonlinear analysis process, NLFEA establishes the instantaneous stiffness of the structure through effective transfer of the instantaneous axial and flexural rigidities from the sectional level to the element level. The model adopts a displacement field tuning convergence approach that involves single or multiple correction phases satisfying the equilibrium and any user-defined displacement tolerance. The efficiency and accuracy of the proposed NLFEA is verified by comparison with test and analytical results from previous studies conducted on undamaged and corrosion-damaged structural elements. NLFEA proves to have high numerical stability and fast convergence, establishing its adoptability in large structural analysis/assessment frameworks. For corrosion-damaged beamcolumns, it is found that critical design sections do not necessarily remain critical for the structural evaluation.

Accuracy of specimen-specific nonlinear finite element analysis for evaluation of distal radius strength in cadaver material

BackgroundDistal radius fracture, which often occurs in the setting of osteoporosis, can lead to permanent deformity and disability. Great effort has been directed toward developing noninvasive methods for evaluating the distal radius strength, with the goal of assessing fracture risk. The aim of this study was to evaluate distal radius strength using a finite element model and to gauge the accuracy of finite element model measurement using cadaver material. MethodsTen wrists were obtained from cadavers with a mean age of 89.5 years at death. CT images of each wrist in an extended position were obtained. CT-based finite element models were prepared with Mechanical Finder software. Fracture on the models was simulated by applying a mechanical load to the palm in a direction parallel to the forearm axis, after which the fracture load and the site at which the fracture began were identified. For comparison, the wrists were fractured using a universal testing machine and the fracture load and the site of fracture were identified. ResultsThe fracture load was 970.9N in the finite element model group and 990.0N in the actual measurement group. The site of the initial fracture was extra-articular to the distal radius in both groups. The finite element model was predictive for distal radius fracture when compared to the actual measurement. ConclusionsIn this study, a finite element model for evaluation of distal radius strength was validated and can be used to predict fracture risk. We conclude that a finite element model is useful for the evaluation of distal radius strength. Knowing distal radius strength might avoid distal radius fracture because appropriate antiosteoporotic treatment can be initiated.

Three-Dimensional Finite Element Model for Evaluation the Stress Intensity Factors for Different Fracture Modes of Homogeneous Bimaterial

The failure of cracked components is governed by the stresses in the vicinity of the crack tip. The singular stress contribution is characterized by stress intensity factors. The stress intensity factors depend on the geometry of the component and on loading condition. This paper addresses the evaluation of stress intensity factors (SIFs) of opening, shearing and tearing modes for compact tension specimens for bonding homogeneous materials. The aim of this work is to find the optimal pre-cracked length, crack notch radius and crack notch angle in order to eliminate the effect of them on the SIF and then on the Fracture toughness. To achieve this goal, a three-dimension finite element analysis (FEA) model using ANSYS program is constructed for specimens made of homogeneous materials such as stainless steel bonding with epoxy as a filler material. The effects of notch angle, notch tip radius and pre-crack length on the stress intensity factors are studied for different fracture modes. The results for the stress intensity factors KI , KII and KIII are obtained using linear elastic fracture mechanics (LEFM) approach.

A finite element model for evaluation of tibial prosthesis-bone interface in total knee replacement

A numerical model based on the finite element method was developed for the load transfer analysis at the tibial bone-implant interfaces in total knee replacement. A transverse isotropic material model, based on a quadratic elastic potential and on Hill's quadratic yield criterion, was next developed for bone constitutive laws. The bone-cement and bone-prosthesis interfaces were both assumed to be discontinuous. A dry friction model based on Coulomb's criterion was adopted for the interfaces friction. The model was shown to be able to give compressive and shear stresses distributions and distractive and relative shear micromotions at these interfaces. A preliminary application was conducted for cemented metal tray total condylar (MTTC) and for cemented and uncemented porous coated anatomic (PCA) tibial plateaus. The PCA plateaus were found to be more deformable and had greater global displacements than the MTTC one. Debonding of the bone-peg interface was observed for the uncemented PCA. Correspondingly, the stress peaks at the interface beneath the tray were lower for the PCA than for the MTTC. Shear micromotions appeared under the tray for both the two prostheses. We observed that bone anisotropy and interface discontinuity affected the results sensibly.