scholarly journals Primary fixation of a finite element model of AI-Hip cementless stem evaluated by micromotion and von Mises stress

2009 ◽  
Vol 33 (1) ◽  
pp. 73-79
Author(s):  
Rina SAKAI ◽  
Yusuke SATO ◽  
Moritoshi ITOMAN ◽  
Kiyoshi MABUCHI
Author(s):  
Raed E. El-Jawahri ◽  
Jesse S. Ruan ◽  
Stephen W. Rouhana ◽  
Saeed D. Barbat

The Ford Motor Company Human Body Finite Element Model (FHBM) was validated against rib dynamic tension and 3-point bending tests. The stress-strain and moment-strain data from the tension and bending simulations respectively were compared with human rib specimen test data. The model used represented a 50th percentile adult male. It was used to compare chest deflection and chest acceleration as thoracic injury indicator in blunt impact and belted occupants in front sled impact simulations. A 150 mm diameter of 23.4 kg impactor was used in the blunt impact simulations with impact speeds of 2, 4, and 8 m/s. In the Front sled impact simulations, single-step acceleration pulses with peaks of 10, 20, and 30 g were used. The occupants were restrained by 3-point belt system, however neither pretensioner nor shoulder belt force limiter were used. The external force, head acceleration, chest deflection, chest acceleration, and the maximum values of Von Mises stress and plastic strain were the model outputs. The results showed that the external contact force, head acceleration, chest deflection, and chest acceleration in the blunt impact simulations varied between 1.5–7 kN, 5–28 g, 18–80 mm, and 8–40 g respectively. The same responses varied between 7–24 kN, 13–40 g, 15–50 mm, and 16–46 g respectively in the front sled impact simulations. The maximum Von Mises stress and plastic strain were 50–127 MPa, and 0.04–2% respectively in the blunt impact simulations and 72–134 MPa, and 0.13–3% respectively in the sled impact simulations.


2017 ◽  
Vol 7 ◽  
pp. 87-93
Author(s):  
Harshal Ashok Patil ◽  
Pawankumar Dnyandeo Tekale ◽  
Veerendra V. Kerudi ◽  
Jitendra S. Sharan ◽  
Ratnadip Arunrao Lohakpure ◽  
...  

ObjectiveThe study conducted to assess the effects of a fixed functional appliance (Forsus Fatigue Resistant Device; 3M Unitek, Monrovia, CA, USA) on the mandible with three-dimensional (3D) finite element stress analysis.Materials and MethodsA 3D finite element model of mandible with miniplate at mandibular symphysis was prepared using SolidEdge software along with the plate geometry. The changes were deliberated with the finite element method, in the form of highest von Mises stress and maximum principal stress regions.ResultsMore areas of stress were seen in the model of the mandible at cortical bone in canine region at bone and miniplate interface.ConclusionsThis fixed functional appliance studied by finite element model analysis caused more von Mises stress and principal stress in both the cortical bone and the condylar region.


2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988526
Author(s):  
Toru Hamasaki ◽  
Masami Iwamoto

Skin deformation caused by contact with an object is transduced into nerve signals by tactile mechanoreceptors, allowing humans to perceive tactile information. Previous research has revealed that the mechanical state associated with finger skin deformation at mechanoreceptor locations in a finite element model is correlated with the experimentally measured responses of slowly adapting type I mechanoreceptors. However, these findings were obtained under static contact conditions. Therefore, in this study, we calculated the von Mises stress at slowly adapting type I and rapidly adapting type I mechanoreceptor locations during dynamic scanning of a textured surface using a finite element model of the human finger. We then estimated the hypothetical responses of the mechanoreceptors and compared the estimated results with the nerve firing of the receptors in previous neurophysiological experiments. These comparisons demonstrated that the temporal history of von Mises stress at mechanoreceptor locations was more strongly correlated with the “number of” impulses (R2 = 0.93 for slowly adapting type I and R2 = 0.90 for rapidly adapting type I) than the impulse “rate” (R2 = 0.58 for slowly adapting type I and R2 = 0.53 for rapidly adapting type I). Our findings suggest that the temporal history of von Mises stress can be used to roughly estimate the number of impulses of mechanoreceptors during scanning of a textured surface.


2020 ◽  
Vol 12 (1) ◽  
pp. 3
Author(s):  
Shuvodeep De ◽  
Karanpreet Singh ◽  
Junhyeon Seo ◽  
Rakesh K. Kapania ◽  
Erik Ostergaard ◽  
...  

The paper describes a fully automated process to generate a shell-based finite element model of a large hybrid truck chassis to perform mass optimization considering multiple load cases and multiple constraints. A truck chassis consists of different parts that could be optimized using shape and size optimization. The cross members are represented by beams, and other components of the truck (batteries, engine, fuel tanks, etc.) are represented by appropriate point masses and are attached to the rail using multiple point constraints to create a mathematical model. Medium-fidelity finite element models are developed for front and rear suspensions and they are attached to the chassis using multiple point constraints, hence creating the finite element model of the complete truck. In the optimization problem, a set of five load conditions, each of which corresponds to a road event, is considered, and constraints are imposed on maximum allowable von Mises stress and the first vertical bending frequency. The structure is optimized by implementing the particle swarm optimization algorithm using parallel processing. A mass reduction of about 13.25% with respect to the baseline model is achieved.


2021 ◽  
Vol 3 (5) ◽  
pp. 3352-3371
Author(s):  
César Alberto Chagoyen Méndez ◽  
Sergio Alejandro Rojas Pérez ◽  
Ernesto Luciano Chagoyen Méndez ◽  
Constantina Álvarez Peña ◽  
Aristides Rivera Torres ◽  
...  

El cálculo de las estructuras de soporte para señalizaciones viales se realiza mediante la norma AASHTO con la cual se realiza fundamentalmente el chequeo a Fatiga, pero con ella no se llegan a conocer las tensiones von Mises, las tensiones tangenciales ni los desplazamientos en cualquier punto de la estructura. En el presente trabajo se determinan las cargas actuantes, así como sus combinaciones más críticas para el análisis. Se realiza el cálculo analítico a través de los métodos y las normas establecidas para ello y se confecciona un modelo de elementos finitos cuya simulación numérica complementa los resultados obtenidos por las normas.   The calculation of the support structures for highway signs is carried out by means of the AASHTO standard, with which the Fatigue check is fundamentally carried out, but with it the von Mises stress, the tangential stress and the displacements at any point of the structure are not known. In the present work, the acting loads are determined, as well as their most critical combinations for the analysis. The analytical calculation is performed through the methods and standards established for it and a finite element model is created whose numerical simulation complements the results obtained by the standards.


2021 ◽  
Author(s):  
Ausberto Velasquez Garcia ◽  
Farid Salamé Castillo ◽  
Max Ekdahl ◽  
Joaquin Mura Mardones

Abstract Background: Postoperative acromioclavicular (AC) ligament deficiency has been identified as a common cause of failure after isolated coracoclavicular reconstruction. The two-bundle arrangement of the acromioclavicular ligament has recently been reported in histological and anatomical research. In addition, a clear structural advantage of the superoposterior bundle (SPB) over the less consistent anteroinferior bundle (AIB) was also found. However, the current understanding of the function of the acromioclavicular ligament in joint stability is based on uniaxial bone loading experiments and sequential ligament sectioning. Consequently, these rigid biomechanics models do not reproduce the coupled physiological kinematics, neither in the normal joint nor in the postoperative condition. Therefore, our goal was to build a dynamic finite element model to study the function of the acromioclavicular ligament based on its biomechanical performance patterns using the benefits of computational models.Methods: A three-dimensional bone model is reconstructed using images from a healthy shoulder. The ligament structures were modeled according to the architecture and dimensions of the bone. The kinematics conditions for the shoulder girdle were determined after the osseous axes aligned to simulate the shoulder elevation in the coronal plane and horizontal adduction. Three patterns evaluated ligament function. The peak von Mises stress values were recorded using a clock model that identified the stress distribution. In addition, the variation in length and displacement of the ligament during shoulder motion were compared using a two-tailed hypotheses test. P values < 0.01 were considered statistically significant.Results: The peak von Mises stress was consistently observed in the AIB at 2:30 in coronal elevation (4.058 MPa) and horizontal adduction (2.323 MPa). Except in the position 2:00, statistically significant higher deformations were identified in the two bundles during shoulder elevation. The highest ligament displacement was observed on the Y- and Z- axes. Conclusions: The AIB has the primary role in restricting the acromioclavicular joint during shoulder motion, even though the two bundles of the AC ligament have a complementary mode of action. During horizontal adduction, the SPB appears to prevent anterior and superior translation.


2021 ◽  
Author(s):  
Sinan Yıldırım ◽  
Ufuk Çoban ◽  
Mehmet Çevik

Suspension linkages are one of the fundamental structural elements in each vehicle since they connect the wheel carriers i.e. axles to the body of the vehicle. Moreover, the characteristics of suspension linkages within a suspension system can directly affect driving safety, comfort and economics. Beyond these, all these design criteria are bounded to the package space of the vehicle. In last decades, suspension linkages have been focused on in terms of design development and cost reduction. In this study, a control arm of a diesel public bus was taken into account in order to get the most cost-effective design while improving the strength within specified boundary conditions. Due to the change of the supplier, the control arm of a rigid axle was redesigned to find an economical and more durable solution. The new design was analyzed first by the finite element analysis software Ansys and the finite element model of the control arm was validated by physical tensile tests. The outputs of the study demonstrate that the new design geometry reduces the maximum Von Mises stress 15% while being within the elastic region of the material in use and having found an economical solution in terms of supplier’s criteria.


2014 ◽  
Vol 607 ◽  
pp. 713-716
Author(s):  
Wen Liang Tang ◽  
Chun Yue Huang ◽  
Tian Ming Li ◽  
Ying Liang ◽  
Guo Ji Xiong ◽  
...  

In this paper, ANSYS-LSDYNA simulation software is used to build the three-dimensional finite element model of the ball bond and to get the Von Mises stress. The change of stress about the bump is researched which base on the model in different bonding pressure, bonding power and bonding time. The result show that: The stress increase with bonding pressure increase within a certain bonding pressure range, and then the stress will maintain a table number, however, the stress will continue to increase when the bonding pressure reach a certain value; increasing the bonding power, the area of lager stress will grow; prolonging the bonding time, the stress of the pad will increase with time, but when time increase to a certain value, the stress of the pad will not increase over time.


Author(s):  
Xiaoben Liu ◽  
Hong Zhang ◽  
Mengying Xia ◽  
Yanfei Chen ◽  
Kai Wu ◽  
...  

Pipelines in service always experience complicated loadings induced by operational and environmental conditions. Flood is one of the common natural hazard threats for buried steel pipelines. One exposed river crossing X70 gas pipeline induced by flood erosion was used as a prototype for this study. A mechanical model was established considering the field loading conditions. Morison equations were adopted to calculate distributional hydrodynamic loads on spanning pipe caused by flood flow. Nonlinear soil constraint on pipe was considered using discrete nonlinear soil springs. An explicit solution of bending stiffness for pipe segment with casing was derived and applied to the numerical model. The von Mises yield criterion was used as failure criteria of the X70 pipe. Stress behavior of the pipe were analyzed by a rigorous finite element model established by the general-purpose Finite-Element package ABAQUS, with 3D pipe elements and pipe-soil interaction elements simulating pipe and soil constraints on pipe, respectively. Results show that, the pipe is safe at present, as the maximum von Mises stress in pipe with the field parameters is 185.57 MPa. The critical flow velocity of the pipe is 5.8 m/s with the present spanning length. The critical spanning length of the pipe is 467 m with the present flow velocity. The failure pipe sections locate at the connection point of the bare pipe and the pipe with casing or the supporting point of the bare pipe on riverbed.


2005 ◽  
Vol 127 (3) ◽  
pp. 484-493 ◽  
Author(s):  
Robert Jackson ◽  
Itti Chusoipin ◽  
Itzhak Green

This work presents a finite element model (FEM) of the residual stresses and strains that are formed after an elastoplastic hemispherical contact is unloaded. The material is modeled as elastic perfectly plastic and follows the von Mises yield criterion. The FEM produces contours for the normalized axial and radial displacements as functions of the removed interference depth and location on the surface of the hemisphere. Contour plots of the von Mises stress and other stress components are also presented to show the formation of the residual stress distribution with increasing plastic deformation. This work shows that high residual von Mises stresses appear in the material pileup near the edge of the contact area after complete unloading. Values are defined for the minimum normalized interference, that when removed, results in plastic residual stresses. This work also defines an interference at which the maximum residual stress transitions from a location below the contact region and along the axis of symmetry to one near to the surface at the edge of the contact radius (within the pileup).


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