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Finite element analysis

Lauren A Burt, Sharon Gaudet, Michelle Kan, Marianne S Rose, Emma O Billington, Steven K Boyd, David A Hanley
The optimum dose of vitamin D and corresponding serum 25-hydroxyvitamin D (25OHD) concentration for bone health is still debated and some health practitioners are recommending doses well above the Canada/USA recommended Dietary Reference Intake (DRI). We designed a three-year randomized double-blind clinical trial investigating whether there are dose-dependent effects of vitamin D supplementation above the Dietary Reference Intake (DRI) on bone health. The primary aims of this study are to assess, whether supplementation of vitamin D3 increases 1) volumetric bone mineral density measured by high-resolution peripheral quantitative computed tomography (HR-pQCT); 2) bone strength assessed by finite element analysis, and 3) areal bone mineral density by dual X-ray absorptiometry (DXA)...
February 19, 2018: Contemporary Clinical Trials
Yongtao Lu, Yue Liu, Chengwei Wu, Junyan Li
Osteoporosis is the most common bone disease. However, the mechanism of osteoporosis-induced alterations in bone is still unclear. The aim of this study was to investigate the effects of osteoporosis on the structural, densitometric and mechanical properties of the whole tibia using in vivo μCT imaging, spatiotemporal analysis and finite element modeling. Twelve C57Bl/6 female mice were adopted. At 14 weeks of age, half of the mice were ovariectomized (OVX), and the other half were SHAM-operated. The whole right tibia was scanned using an in vivo μCT imaging system at 14, 16, 17, 18, 19, 20, 21 and 22 weeks...
February 22, 2018: Annals of Biomedical Engineering
Kaihua Sun, Ling Yuan, Zhonghua Shen, Qingping Zhu
This study aims to evaluate early caries in human teeth with different geometry structures by using the dispersion curves of a surface acoustic wave (SAW) generated by a pulsed laser. Through the finite element method, SAWs propagating on teeth models with different enamel thickness and curvature radius were simulated, and the influence of the geometry difference on the dispersion curves of SAWs was discussed. Laser ultrasonic experiments were performed on an extracted human incisor and molar with different demineralization conditions...
February 10, 2018: Applied Optics
J-C Escudier, M Ollivier, M Donnez, S Parratte, P Lafforgue, J-N Argenson
INTRODUCTION: Recent reports described possible mechanical factors in the development and aggravation of osteonecrosis of the femoral head (OFH), but these have yet to be confirmed on dedicated mechanical study. We therefore developed a 3D finite element model based on in-vivo data from patients with incipient OFH, with a view to determining whether the necrosis area was superimposed on the maximal stress area on the femoral head. HYPOTHESIS: The location of the necrosis area is determined by stress on the femoral head...
February 17, 2018: Orthopaedics & Traumatology, Surgery & Research: OTSR
Dong Hyun Chun, Do Heum Yoon, Keung Nyun Kim, Seong Yi, Dong Ah Shin, Yoon Ha
STUDY DESIGN: Finite element analysis. OBJECTIVE: To compare the biomechanical stability imparted to the C1 and C2 vertebrae by the transarticular(TA), C1 lateral mass(LM)-C2 pedicle(PS), C1LM-C2 pars, and C1LM-C2 translaminar screw(TL) fixation techniques. SUMMARY OF BACKGROUND DATA: Cadaveric biomechanical studies of several atlantoaxial posterior fixation techniques have been performed, showing significant heterogeneity in biomechanical properties among the studies...
February 16, 2018: Spine
Venkateswaran Santhanakrishnan Balakrishnan, Holger Seidlitz, Sabine Weiß
The current trend shows an increasing demand for composites due to their high stiffness to weight ratio and the recent progress in manufacturing and cost reduction of composites. To combine high strength and stiffness in a cost-effective way, composites are often joined with steel or aluminum. However, joining of thermoset composite materials is challenging because circular holes are often used to join them with their metal counterparts. These design based circular holes induce high stress concentration around the hole...
February 20, 2018: Materials
Zhiping Kuang, Guanyu Zheng
Owing to its controllable tolerance, simple operation and no need for welding at construction site, the composite system involving grouted cement material, steel material and ductile iron material is widely used as grouted splice sleeve (GSS) connector for connecting precast concrete structures. However, the current design recommendations for such a composite connection system do not accurately account for its material nonlinearity behavior. In the present study, a three-dimensional nonlinear finite element model of a GSS connector is developed by considering the nonlinear material behavior of each component to fully investigate its mechanical performance under axial tension...
February 20, 2018: Materials
Mehmet Emin Cetin, Hasan Sofuoglu
This study was carried out to determine mechanical behavior and bone adaptation of total hip arthroplasty (THA) subject to concentrated and distributed muscle loads and hip contact forces during activities of walking and stair climbing. Finite element modeling of THA with different prostheses, activity and loading types was developed by adopting a statistical method. Two levels of prostheses, activity, and loading types were selected for the study. 23 factorial method was then pursued to design input and output data of finite element analysis...
February 19, 2018: Australasian Physical & Engineering Sciences in Medicine
Wen-Wei Shen, Yu-Min Lin, Sheng-Tsai Wu, Chia-Hsin Lee, Shin-Yi Huang, Hsiang-Hung Chang, Tao-Chih Chang, Kuan-Neng Chen
In this study, through silicon via (TSV)-less interconnection using the fan-out wafer-level-packaging (FO-WLP) technology and a novel redistribution layer (RDL)-first wafer level packaging are investigated. Since warpage of molded wafer is a critical issue and needs to be optimized for process integration, the evaluation of the warpage issue on a 12-inch wafer using finite element analysis (FEA) at various parameters is presented. Related parameters include geometric dimension (such as chip size, chip number, chip thickness, and mold thickness), materials' selection and structure optimization...
August 1, 2018: Journal of Nanoscience and Nanotechnology
Maria Carla Piastra, Andreas Nüßing, Johannes Vorwerk, Harald Bornfleth, Robert Oostenveld, Christian Engwer, Carsten H Wolters
In Electro- (EEG) and Magnetoencephalography (MEG), one important requirement of source reconstruction is the forward model. The continuous Galerkin finite element method (CG-FEM) has become one of the dominant approaches for solving the forward problem over the last decades. Recently, a discontinuous Galerkin FEM (DG-FEM) EEG forward approach has been proposed as an alternative to CG-FEM (Engwer et al., 2017). It was shown that DG-FEM preserves the property of conservation of charge and that it can, in certain situations such as the so-called skull leakages , be superior to the standard CG-FEM approach...
2018: Frontiers in Neuroscience
Yong-Hua Zhang, Stephen A Campbell, Sreejith Karthikeyan
Transdermal drug delivery (TDD) based on microneedles is an excellent approach due to its advantages of both traditional transdermal patch and hypodermic syringes. In this paper, the fabrication method of hollow out-of-layer hafnium oxide (HfO2 ) microneedles mainly based on deep reactive ion etching of silicon and atomic layer deposition of HfO2 is described, and the finite element analysis of the microneedles based on ANSYS software is also presented. The fabrication process is simplified by using a single mask...
February 17, 2018: Biomedical Microdevices
M E T Silva, M P L Parente, S Brandão, T Mascarenhas, R M Natal Jorge
The mechanical characteristics of the female pelvic floor are relevant to understand pelvic floor dysfunctions (PFD), and how they are related with changes in their biomechanical behavior. Urinary incontinence (UI) and pelvic organ prolapse (POP) are the most common pathologies, which can be associated with changes in the mechanical properties of the supportive structures in the female pelvic cavity. PFD have been studied through different methods, from experimental tensile tests using tissues from fresh female cadavers or tissues collected at the time of a transvaginal hysterectomy procedure, or by applying imaging techniques...
February 8, 2018: Journal of Biomechanics
Hong Gi Yoon, Hyun Keun Oh, Dong-Yul Lee, Joo-Hee Shin
Objective The purpose of this study was to evaluate, by using finite element analysis, the influence of post location and occlusal loading location on the stress distribution pattern inside the root canals of the mandibular 1st molar. Material and Methods Three different 3-D models of the mandibular 1st molar were established: no post (NP) - a model of endodontic and prosthodontic treatments; mesiobuccal post (MP) - a model of endodontic and prosthodontic treatments with a post in the mesiobuccal canal; and distal post (DP) - a model of endodontic and prosthodontic treatments with a post in the distal canal...
2018: Journal of Applied Oral Science: Revista FOB
Adam D Sylvester, Patricia A Kramer
Finite element analysis (FEA) is a powerful tool for evaluating questions of functional morphology, but the application of FEA to extant or extinct creatures is a non-trivial task. Three categories of input data are needed to appropriately implement FEA: geometry, material properties, and boundary conditions. Geometric data are relatively easily obtained from imaging techniques, but often material properties and boundary conditions must be estimated. Here we conduct sensitivity analyses of the effect of the choice of Young's Modulus for elements representing trabecular bone and muscle loading complexity on the proximal femur using a finite element mesh of a modern human femur...
February 16, 2018: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Young-Gon Kim, Kuk-Hyun Song, Dong-Hoon Lee, Sung-Min Joo
The demand of crack tip opening displacement (CTOD) test which evaluates fracture toughness of a cracked material is very important to ensure the stability of structure under severe service environment. The validity of the CTOD test result is judged using several criterions of the specification standards. One of them is the artificially generated fatigue pre-crack length inside the specimen. For acceptable CTOD test results, fatigue pre-crack must have a reasonable sharp crack front. The propagation of fatigue crack started from the tip of the machined notch, which might have propagated irregularly due to residual stress field...
March 1, 2018: Journal of Nanoscience and Nanotechnology
Yoshihisa Tanaka, Shinichiro Nakamura, Shinichi Kuriyama, Kohei Nishitani, Hiromu Ito, Moritoshi Furu, Mutsumi Watanabe, Shuichi Matsuda
BACKGROUND: Kinematically aligned total knee arthroplasty is based on the concept to represent the premorbid joint alignment with cruciate-retaining implants, characterized by medial tilt and internal rotation. However, kinematic and kinetic effects of kinematically aligned total knee arthroplasty with posterior-stabilized implants is unknown. The purpose of this study was to examine the effect of medial tilting of the joint line with posterior-stabilized implants. METHODS: A mechanical alignment model, and medial tilt 3° and 5° models were constructed...
February 9, 2018: Clinical Biomechanics
Cheolwoong Ko, Mikyung Yang, Taemin Byun, Sang-Wook Lee
This study proposed a way to design femur fracture fixation plates made of shape memory alloy based on CT (Computed Tomography) images of Korean cadaveric femurs. To this end, 3 major design factors of femur fracture fixation plates (circumference angle, thickness, and inner diameter) were selected based on the contact pressure when a femur fracture fixation plate was applied to a cylinder model using the Taguchi Method. Then the effects of the design factors were analyzed. It was shown that the design factors were statistically significant at a level of p=0...
February 15, 2018: International Journal for Numerical Methods in Biomedical Engineering
Alexander Blanke, Manuel Pinheiro, Peter J Watson, Michael J Fagan
Insect head shapes are remarkably variable but the influences of these changes on biomechanical performance are unclear. Among "basal" winged insects, such as dragonflies, mayflies, earwigs, and stoneflies, some of the most prominent anatomical changes are the general mouthpart orientation, eye size and the connection of the endoskeleton to the head. Here, we assess these variations as well as differing ridge and sclerite configurations using modern engineering methods including multibody dynamics modelling and finite element analysis in order to quantify and compare the influence of anatomical changes on strain in particular head regions and the whole head...
February 14, 2018: Journal of Evolutionary Biology
Zhen Hua, Jian-Wei Wang, Zhen-Fei Lu, Jian-Wei Ma, Heng Yin
BACKGROUND: The distal radius fracture is one of the common clinical fractures. At present, there are no reports regarding application of the finite element method in studying the mechanism of Colles fracture and the biomechanical behavior when using splint fixation. OBJECTIVE: To explore the mechanism of Colles fracture and the biomechanical behavior when using different fixed splints. METHODS: Based on the CT scanning images of forearm for a young female volunteer, by using model construction technology combined with RPOE and ANSYS software, a 3-D distal radius fracture forearm finite element model with a real shape and bioactive materials is built...
January 30, 2018: Technology and Health Care: Official Journal of the European Society for Engineering and Medicine
M Pinheiro, C A Dobson, D Perry, M J Fagan
OBJECTIVES: Legg-Calvé-Perthes' disease (LCP) is an idiopathic osteonecrosis of the femoral head that is most common in children between four and eight years old. The factors that lead to the onset of LCP are still unclear; however, it is believed that interruption of the blood supply to the developing epiphysis is an important factor in the development of the condition. METHODS: Finite element analysis modelling of the blood supply to the juvenile epiphysis was investigated to understand under which circumstances the blood vessels supplying the femoral epiphysis could become obstructed...
February 2018: Bone & Joint Research
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