scholarly journals Gait-Specific Optimization of Composite Footwear Midsole Systems, Facilitated through Dynamic Finite Element Modelling

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Dimitris Drougkas ◽  
Evagelos Karatsis ◽  
Maria Papagiannaki ◽  
Serafeim Chatzimoisiadis ◽  
Fotini Arabatzi ◽  
...  
Keyword(s):  
Finite Element ◽  
Nonlinear Material ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Fe Modelling ◽  
Plantar Pressure Distribution ◽  
Optimization Function ◽  
Modelling Techniques ◽  
Mesh Grid

Objective. During the last century, running shoes have been subject to drastic changes with incremental however improvements as to injury prevention. This may be, among others, due to the limited insight that experimental methodologies can provide on their 3D in situ response. The objective of this study was to demonstrate the effectiveness of finite element (FE) modelling techniques, in optimizing a midsole system as to the provided cushioning capacity. Methods. A commercial running shoe was scanned by means of micro computed tomography and its gel-based midsole, reverse-engineered to a 200 μm accuracy. The resulting 3D model was subjected to biorealistic loading and boundary conditions, in terms of time-varying plantar pressure distribution and shoe-ground contact constraints. The mesh grid of the FE model was verified as to its conceptual soundness and validated against velocity-driven impact tests. Nonlinear material properties were assigned to all entities and the model subjected to a dynamic FE analysis. An optimization function (based on energy absorption criteria) was employed to determine the optimum gel volume and position, as to accommodate sequential cushioning in the rear-, mid-, and forefoot, of runner during stance phase. Results. The in situ developing stress fields suggest that the shock dissipating properties of the midsole could be significantly improved. Altering the position of the gel pads and varying their volume led to different midsole responses that could be tuned more efficiently to the specific strike and pronation pattern. Conclusions. The results suggest that midsole design can be significantly improved through biorealistic FE modelling, thus providing a new platform for the conceptual redesign and/or optimization of modern footwear.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

Evaluating the Mechanical Behavior of 316 Stainless Steel at the Microscale Using Finite Element Modelling and In-Situ Neutron Scattering

2010 ◽  
Author(s):  
Dong-Feng Li ◽  
Noel P. O’Dowd ◽  
Catrin M. Davies ◽  
Shu-Yan Zhang
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Modelling ◽  
Mechanical Response ◽  
Fe Model ◽  
Lattice Strains ◽  
Crystallographic Slip ◽  
In Situ Neutron Diffraction ◽  
Elastic Lattice

In this study, the deformation behavior of an austenitic stainless steel is investigated at the microscale by means of in-situ neutron diffraction (ND) measurements in conjunction with finite-element (FE) simulations. Results are presented in terms of (elastic) lattice strains for selected grain (crystallite) families. The FE model is based on a crystallographic (slip system based) representation of the deformation at the microscale. The present study indicates that combined in-situ ND measurement and micromechanical modelling provides an enhanced understanding of the mechanical response at the microscale in engineering steels.

The Effect of Trabecular Bone on the Mechanical Response of Human Mandible with Implant

2014 ◽  
Vol 695 ◽  
pp. 588-591
Author(s):  
Khairul Salleh Basaruddin ◽  
Ruslizam Daud
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Trabecular Bone ◽  
Static Analysis ◽  
Load Distribution ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Bone Specimen

This study aims to investigate the influence of trabecular bone in human mandible bone on the mechanical response under implant load. Three dimensional voxel finite element (FE) model of mandible bone was reconstructed from micro-computed tomography (CT) images that were captured from bone specimen. Two FE models were developed where the first consists of cortical bone, trabecular bone and implants, and trabecular bone part was excluded in the second model. A static analysis was conducted on both models using commercial software Voxelcon. The results suggest that trabecular bone contributed to the strength of human mandible bone and to the effectiveness of load distribution under implant load.

scholarly journals Finite Element Modelling and Updating of Welded Thin-Walled Beam

2018 ◽  
Vol 15 (4) ◽  
pp. 5874-5889 ◽  
Author(s):  
M. S. M. Fouzi ◽  
K. M. Jelani ◽  
N. A. Nazri ◽  
Mohd Shahrir Mohd Sani
Keyword(s):  
Finite Element ◽  
Model Updating ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Modal Parameters ◽  
Fe Model ◽  
Fe Modelling ◽  
Welded Structure ◽  
Thin Walled ◽  
Fe Model Updating

This article concentrates on the finite element (FE) modelling approach to model welded thin-walled beam and the adoption of model updating technique to enhance the dynamic characteristic of the FE model. Four different types of element connectors which are RBE2, CBAR, CBEAM and CELAS format are used to construct the FE model of welded structure. Normal mode analysis is performed using finite element analysis (FEA) software, MSC Patran/Nastran to extract the modal parameters (natural frequency and mode shape) of the FE model. The precision of predicted modal parameters obtained from the four models of welded structure are compared with the measured counterparts. The dynamic characteristics of a measured counterpart is obtained through experimental modal analysis (EMA) using impact hammer method with roving accelerometer under free-free boundary conditions. In correlation process, the CBAR model has been selected for updating purposes due to its accuracy in prediction with measured counterparts and contains updating parameters compared to the others. Ahead of the updating process, sensitivity analysis is made to select the most sensitive parameter for updating purpose. Optimization algorithm in MSC Nastran is used in FE model updating process. As a result, the discrepancy between EMA and FEA is managed to be reduced. It shows the percentage of error for updated CBAR model shrinks from 7.85 % to 2.07 % when compared with measured counterpart. Hence, it is found that using FE model updating process provides an efficient and systemic way to perform a feasible FE model in replicating the real structure.

scholarly journals Moisture Induced Deformations in Glulam Members - Experiments and 3-D Finite Element Model

2017 ◽  
Vol 36 (2) ◽  
pp. 35-45
Author(s):  
Henry M. Kiwelu
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Solid Wood ◽  
Average Moisture Content ◽  
Fe Model ◽  
Fe Modelling ◽  
Average Value ◽  
Hybrid Buildings ◽  
External Shape

Experiments were performed on scaled glue laminated bending specimens to observetime dependent development of deformations during drying and wetting. Measurementsdetermined changes in the average moisture content and external shape and dimensionsbetween when specimens were placed into constant or variable climates. Alterations inthe external shape and dimensions reflected changes in the average value anddistribution of moisture and mechanosorptive creep in the glulam. The results are beingused to develop a sequentially-coupled three-dimensional hygrothermal Finite Element(FE) model for predicting temporally varying internal strains and external deformationsof drying or wetting solid wood structural components. The model implies temporallyvarying, and eventual steady, state internal stress distributions in members based onelastic and creep compliances that represent wood within glulam as a continuousorthotropic homogenised material. Thus, predictions are consistent with smearedengineering stress analysis methods rather than being a physically correct analogue ofhow solid wood behaves. This paper discusses limitations of and intended improvementsto the FE modelling. Complementary investigations are underway to address otheraspects of the hygrothermal behaviour of structural members of wood and othermaterials (e.g. reinforced concrete) embedded within superstructure frameworks ofmulti-storey hybrid buildings.

Automated Segmentation of Swine Skulls for Finite Element Model Creation Using High Resolution μ-CT Images

2019 ◽  
Vol 16 (03) ◽  
pp. 1842012 ◽  
Author(s):  
Zimo Zhu ◽  
Donna C. Jones ◽  
G. R. Liu ◽  
Sajjad Soleimani ◽  
Xu Huang ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Complex Structure ◽  
Model Development ◽  
Element Model ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Mineral Density ◽  
Detailed Model ◽  
Bone Mineral Density Loss

Finite element (FE) analysis has been widely used to investigate bone responses to mechanical loading. Research in long bones has been straight forward because modeling of these bones requires only two material properties. Such an FE model may provide an adequate approximation of the anatomy for many cases. However, a more detailed model of skull bones is needed to accurately capture its complex structure of multiple bone pieces and the various mineral densities distributed throughout these bone pieces. Unfortunately, FE model development incorporating both complex geometries and anatomically accurate material properties is both computationally and labor intensive. In this study, a method is proposed to automatically segment micro-computed tomography ([Formula: see text]-CT) scan images of bone pieces to build an FE model of a full swine hemi-skull. Using the Digital Imaging and Communications in Medicine (DICOM) files from scanned bones, the complete geometry of each bone piece is recreated through seven customized processing algorithms. After assembling the bone pieces to form the skull, experimentally derived Young’s modulus values are correlated to grayscale values to produce a detailed FE model for accurate simulation. This detailed skull model can be used to predict strain/stress patterns in response to various loading regimes to facilitate research questions in fracture healing and growth, as well as bone tissue engineering and bone mineral density loss (e.g., osteoporosis).

Alignment Criteria for Through-Wall Flaws in Plates and Pipes

2008 ◽  
Author(s):  
B. Bezensek ◽  
K. Miyazaki
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Damage Model ◽  
Fe Model ◽  
Experimental Sample ◽  
Fe Modelling ◽  
Combination Rules ◽  
Single Flaw

Multiple flaws in vessels and pipes are frequently assessed as a larger single flaw in accordance with the flaw alignment and combination rules. In this paper the alignment of two through-wall flaws is examined for plates in tension and pipes in bending using detailed finite element (FE) modelling. The FE model is developed using the Gurson-Tvergaard damage model and accurately describes the flaw interaction and load capacity of a random experimental sample. Results suggests that two flaws should be aligned onto the same plane for the purpose of assessment when the separation between the parallel planes containing flaws equals the flaw length for both, plates in tension and pipes in bending.

The Application of Aeroelastic Analysis Output Load Distributions to Finite Element Models of Wind

2005 ◽  
Vol 29 (2) ◽  
pp. 153-168 ◽  
Author(s):  
Timothy J. Knill
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Fe Model ◽  
Wind Turbine Blades ◽  
Fe Modelling ◽  
Load Distributions ◽  
Aeroelastic Analysis ◽  
Extreme Load ◽  
Application Techniques

The structural design of wind turbine blades is a rapidly evolving technology. Finite element (FE) modelling is used extensively by structural designers to assess the behaviour of wind turbine blades under operational and extreme load conditions. This paper develops a method of transferring aerodynamic and inertial loads from the aeroelastic analysis output to the FE model. Once a procedure is developed and verified, case studies are undertaken using an FE model of a 34m blade. Loads are applied using the newly developed method and various FE analysis results compared to the same blade analysed under more traditional load application techniques. The case study clearly demonstrates that the method of applying loads can influence some types of analysis results significantly.

Finite element analysis of intramedullary devices: The effect of the gap between the implant and the bone

2008 ◽  
Vol 222 (3) ◽  
pp. 333-345 ◽  
Author(s):  
D J Simpson ◽  
C J Brown ◽  
A L Yettram ◽  
P Procter ◽  
G J Andrew
Keyword(s):  
Finite Element ◽  
Fracture Plane ◽  
Local Geometry ◽  
Fe Model ◽  
Fe Modelling ◽  
Element Analysis ◽  
Medial Side ◽  
Intramedullary Device ◽  
Interaction Interface ◽  
Distribution Of Stress

This paper examines the interaction interface between the implant and the bone for an intramedullary femoral nailing system using a finite element (FE) model and specifically considers the hypothesis that the local geometry at the interface is significant to the resulting localized contact stress between the medial and lateral aspect of nail and endosteum. Contact mechanics algorithms are used in the FE modelling technique that can be developed to deal with any form of intramedullary device for which contact at the bone—implant interface is important. Global stiffness data from the FE model are compared with available data from an experiment carried out on a construct of the bone and the device that uses intramedullary femoral nails. Acceptable agreement is obtained. The results demonstrate that the mechanical interface between the implant and the bone is significantly affected by the gap geometry and magnitude. In particular, larger gaps lead to greater concentrations of stress on the medial side, while the distribution of stress is more uniform at the lateral contacts. Furthermore, the results show that the gap can have a marked effect on the stresses that occur on the fracture plane.

Finite element modelling of pullout testing on a soil nail in a pullout box under different overburden and grouting pressures

2011 ◽  
Vol 48 (4) ◽  
pp. 557-567 ◽  
Author(s):  
Wan-Huan Zhou ◽  
Jian-Hua Yin ◽  
Cheng-Yu Hong
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Back Analysis ◽  
Soil Mass ◽  
Friction Model ◽  
Soil Parameters ◽  
Fe Model ◽  
Fe Modelling ◽  
Soil Nail ◽  
Pullout Behaviour

In this paper, a three-dimensional (3D) finite element (FE) model is developed to simulate the pullout behaviour of a soil nail in a soil-nail pullout box under different overburden and grouting pressures. The FE model simulates all the procedures of a pullout test on a grouted soil nail in a compacted and saturated completely decomposed granite (CDG) soil. The stress–strain behaviour of the CDG soil is described by a modified Drucker–Prager/Cap model, while that of the soil–nail interface is represented by the Coulomb friction model. Triaxial experiment data are used to calibrate the soil parameters in the soil constitutive model. The interface parameters are determined from back-analysis with the laboratory soil-nail pullout data. The soil stress variations surrounding the soil nail during drilling, grouting, saturation, and pullout are all well simulated by the FE modelling and compared with available test data. The comparisons between the modelling and experimental data have shown that the established FE can well simulate the pullout behaviour of a soil nail in a soil mass. Based on this, the verified FE model has the potential to simulate the performance of a soil nail in a field soil slope.

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