Seat-cushion and soft-tissue material modeling and a finite element investigation of the seating comfort for passenger-vehicle occupants

2009 ◽  
Vol 30 (10) ◽  
pp. 4273-4285 ◽  
Author(s):  
M. Grujicic ◽  
B. Pandurangan ◽  
G. Arakere ◽  
W.C. Bell ◽  
T. He ◽  
...  
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Material Modeling ◽  
Passenger Vehicle ◽  
Seat Cushion ◽  
Seating Comfort ◽  
Tissue Material

Contact Pressure Sensitivity Analysis in N95 Filtering Facepiece Respirator With Strap Location, Friction, and Headform Material Property

2015 ◽  
Author(s):  
Ming Xu ◽  
James Yang
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Pressure Distribution ◽  
Contact Pressure ◽  
Material Property ◽  
Sensitivity Study ◽  
Facial Soft Tissue ◽  
Maximum Contact ◽  
Contact Pressures ◽  
Tissue Material

The contact pressure between an N95 filtering facepiece respirator (FFR) and the human face plays an important role in FFR performance. In this paper, the effects of several important factors (strap locations on headback, friction, and facial soft tissue material property) on contact pressures are studied using validated N95 FFR/headform finite element models. Sixteen different FFR/headform combinations including six FFRs and five digital headforms (small, medium, large, long/narrow, and short/wide) are studied. For each FFR/headform combination, the facial contact pressure distribution is recorded from the finite element results. The maximum contact pressures from six key areas are recorded for sensitivity study. The results show that the strap locations on the headback produce the largest effect on the maximum contact pressure values and the pressure distribution. The friction and the facial soft tissue material property have limited effects on the maximum contact pressure although they can affect the pressure distribution.

scholarly journals Developing a Quantifying Device for Soft Tissue Material Prop-Erties around Lumbar Spines

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 67
Author(s):  
Song Joo Lee ◽  
Yong-Eun Cho ◽  
Kyung-Hyun Kim ◽  
Deukhee Lee
Keyword(s):  
Lumbar Spine ◽  
Soft Tissue ◽  
Young’S Modulus ◽  
Viscoelastic Properties ◽  
Soft Tissues ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress And Strain ◽  
Commercial Device ◽  
Tissue Material

Knowing the material properties of the musculoskeletal soft tissue could be important to develop rehabilitation therapy and surgical procedures. However, there is a lack of devices and information on the viscoelastic properties of soft tissues around the lumbar spine. The goal of this study was to develop a portable quantifying device for providing strain and stress curves of muscles and ligaments around the lumbar spine at various stretching speeds. Each sample was conditioned and applied for 20 repeatable cyclic 5 mm stretch-and-relax trials in the direction and perpendicular direction of the fiber at 2, 3 and 5 mm/s. Our device successfully provided the stress and strain curve of the samples and our results showed that there were significant effects of speed on the young’s modulus of the samples (p < 0.05). Compared to the expensive commercial device, our lower-cost device provided comparable stress and strain curves of the sample. Based on our device and findings, various sizes of samples can be measured and viscoelastic properties of the soft tissues can be obtained. Our portable device and approach can help to investigate young’s modulus of musculoskeletal soft tissues conveniently, and can be a basis for developing a material testing device in a surgical room or various lab environments.

Viscoelastic characterization of soft tissue from dynamic finite element models

2008 ◽  
Vol 53 (22) ◽  
pp. 6569-6590 ◽  
Author(s):  
Hani Eskandari ◽  
Septimiu E Salcudean ◽  
Robert Rohling ◽  
Jacques Ohayon
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Models ◽  
Dynamic Finite Element

The Role of Topology and Tissue Mechanics in Remora Attachment

2014 ◽  
Vol 1648 ◽  
Author(s):  
Michael Culler ◽  
Keri A. Ledford ◽  
Jason H. Nadler
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Tissue Mechanics ◽  
Unit Cell ◽  
Surface Topology ◽  
Finite Element Models ◽  
Cell Geometry ◽  
Critical Step ◽  
Tissue Material

ABSTRACTRemora fish are capable of fast, reversible and reliable adhesion to a wide variety of both natural and artificial marine hosts through a uniquely evolved dorsal pad. This adhesion is partially attributed to suction, which requires a robust seal between the pad interior and the ambient environment. Understanding the behavior of remora adhesion based on measurable surface parameters and material properties is a critical step when creating artificial, bio-inspired devices. In this work, structural and fluid finite element models (FEM) based on a simplified “unit cell” geometry were developed to predict the behavior of the seal with respect to host/remora surface topology and tissue material properties.

Analysis of seat cushion comfort by employing a finite element buttock model as a supplement to pressure measurement

2021 ◽  
Vol 86 ◽  
pp. 103211
Author(s):  
Sunil Kumar Yadav ◽  
Can Huang ◽  
Fuhao Mo ◽  
Junjie Li ◽  
Jianping Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Pressure Measurement ◽  
Seat Cushion

scholarly journals Key considerations for finite element modelling of the residuum–prosthetic socket interface

2020 ◽  
pp. 030936462096778
Author(s):  
JW Steer ◽  
PR Worsley ◽  
M Browne ◽  
Alex Dickinson
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Modelling ◽  
Soft Tissues ◽  
Shear Stresses ◽  
Material Models ◽  
Element Modelling ◽  
Prosthetic Socket ◽  
Highly Nonlinear ◽  
Socket Interface

Background: Finite element modelling has long been proposed to support prosthetic socket design. However, there is minimal detail in the literature to inform practice in developing and interpreting these complex, highly nonlinear models. Objectives: To identify best practice recommendations for finite element modelling of lower limb prosthetics, considering key modelling approaches and inputs. Study design: Computational modelling. Methods: This study developed a parametric finite element model using magnetic resonance imaging data from a person with transtibial amputation. Comparative analyses were performed considering socket loading methods, socket–residuum interface parameters and soft tissue material models from the literature, to quantify their effect on the residuum’s biomechanical response to a range of parameterised socket designs. Results: These variables had a marked impact on the finite element model’s predictions for limb–socket interface pressure and soft tissue shear distribution. Conclusions: All modelling decisions should be justified biomechanically and clinically. In order to represent the prosthetic loading scenario in silico, researchers should (1) consider the effects of donning and interface friction to capture the generated soft tissue shear stresses, (2) use representative stiffness hyperelastic material models for soft tissues when using strain to predict injury and (3) interrogate models comparatively, against a clinically-used control.

scholarly journals Finite Element Modelling Simulated Meniscus Translocation and Deformation during Locomotion of the Equine Stifle

Animals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 502
Author(s):  
Pasquale Zellmann ◽  
Iris Ribitsch ◽  
Stephan Handschuh ◽  
Christian Peham
Keyword(s):  
Finite Element ◽  
Lateral Meniscus ◽  
Element Model ◽  
Magnetic Resonance Images ◽  
Fem Model ◽  
Stifle Joint ◽  
Loading Patterns ◽  
Articular Cartilages ◽  
Tissue Material ◽  
Treatment Surgery

We developed a finite element model (FEM) of the equine stifle joint to identify pressure peaks and simulate translocation and deformation of the menisci. A series of sectional magnetic resonance images (1.5 T) of the stifle joint of a 23 year old Shetland pony gelding served as basis for image segmentation. Based on the 3D polygon models of femur, tibia, articular cartilages, menisci, collateral ligaments and the meniscotibial ligaments, an FEM model was generated. Tissue material properties were assigned based on data from human (Open knee(s) project) and bovine femoro-tibial joint available in the literature. The FEM model was tested across a range of motion of approximately 30°. Pressure load was overall higher in the lateral meniscus than in the medial. Accordingly, the simulation showed higher translocation and deformation in the lateral compared to the medial meniscus. The results encourage further refinement of this model for studying loading patterns on menisci and articular cartilages as well as the resulting mechanical stress in the subchondral bone (femur and tibia). A functional FEM model can not only help identify segments in the stifle which are predisposed to injury, but also to better understand the progression of certain stifle disorders, simulate treatment/surgery effects and to optimize implant/transplant properties.

Quantifying Variability in Lumbar L4-L5 Soft Tissue Properties for Use in Finite-Element Analysis

2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Dana J. Coombs ◽  
Paul J. Rullkoetter ◽  
Peter J. Laz
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Experimental Testing ◽  
Intersubject Variability ◽  
Probabilistic Representation ◽  
Posterior Portion ◽  
Annulus Fibrosis ◽  
Interspinous Ligament ◽  
Constitutive Material Model ◽  
The Impact

Soft tissue structures of the L4-L5 level of the human lumbar spine are represented in finite-element (FE) models, which are used to evaluate spine biomechanics and implant performance. These models typically use average properties; however, experimental testing reports variation up to 40% in ligament stiffness and even greater variability for annulus fibrosis (AF) properties. Probabilistic approaches enable consideration of the impact of intersubject variability on model outputs. However, there are challenges in directly applying the variability in measured load–displacement response of structures to a finite-element model. Accordingly, the objectives of this study were to perform a comprehensive review of the properties of the L4-L5 structures and to develop a probabilistic representation to characterize variability in the stiffness of spinal ligaments and parameters of a Holzapfel–Gasser–Ogden constitutive material model of the disk. The probabilistic representation was determined based on direct mechanical test data as found in the literature. Monte Carlo simulations were used to determine the uncertainty of the Holzapfel–Gasser–Ogden constitutive model. A single stiffness parameter was defined to characterize each ligament, with the anterior longitudinal ligament (ALL) being the stiffest, while the posterior longitudinal ligament and interspinous ligament (ISL) had the greatest variation. The posterior portion of the annulus fibrosis had the greatest stiffness and greatest variation up to 300% in circumferential loading. The resulting probabilistic representation can be utilized to include intersubject variability in biomechanics evaluations.

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