scholarly journals Application of Topology Optimization to Thighbone/Implant Interaction Modelling

2020 ◽  
Author(s):  
Ryszard Kutylowski ◽  
Marek Szwechłowicz
Keyword(s):  
Topology Optimization ◽  
Postoperative Complications ◽  
Material Properties ◽  
Bone Structure ◽  
Mechanical Parameters ◽  
Similar Material ◽  
Accelerated Degradation ◽  
Minimum Compliance ◽  
Interaction Modelling ◽  
Variational Minimum

This paper presents an application of topology optimization in the analysis of the thighbone with an inserted endoprosthesis. A variational minimum compliance approach with mass constraints is employed to solve the problem. Changes in the bone structure depending on the implant’s mechanical parameters are studied. Numerical results for mass distribution in the modelled thighbone with an inserted endoprosthesis are analyzed using an original numerical algorithm and a program developed in Matlab. It is numerically proven that owing to the use of an implant with material properties similar to those of the bone no degradation of the latter in the vicinity of the implant occurs. The endoprosthesis will serve longer and the postoperative complications connected with the accelerated degradation of the bone in the neighborhood of the implant will be avoided if the implant has similar material properties as the bone.

scholarly journals Structural optimization in ESAC: annals 2011

2014 ◽  
Vol 5 ◽  
pp. A09
Author(s):  
Ji-Hong Zhu ◽  
Wei-Hong Zhang
Keyword(s):  
Topology Optimization ◽  
Structural Optimization ◽  
Material Properties ◽  
Numerical Results ◽  
Multiphase Materials ◽  
And Topology ◽  
Effective Material Properties

The purpose of this paper is to give an overall introduction of the structural optimization research works in ESAC group in 2011. Four main topics are involved, i.e. 1) topology optimization with multiphase materials, 2) integrated layout and topology optimization, 3) prediction of effective material properties and 4) composite design. More detailed techniques and some numerical results are also presented and discussed here.

Multi-level patient-specific modelling of the proximal femur. A promising tool to quantify the effect of osteoporosis treatment

2009 ◽  
Vol 367 (1895) ◽  
pp. 2079-2093 ◽  
Author(s):  
Leen Lenaerts ◽  
G. Harry van Lenthe
Keyword(s):  
Bone Strength ◽  
Material Properties ◽  
Bone Structure ◽  
Structural Information ◽  
Response To Treatment ◽  
Patient Specific ◽  
Loading Conditions ◽  
Femoral Bone ◽  
Fe Modelling ◽  
Specific Loading

Preventing femoral fractures is an important goal in osteoporosis research. In order to evaluate a person's fracture risk and to quantify response to treatment, bone competence is best assessed by bone strength. Finite-element (FE) modelling based on medical imaging is considered a very promising technique for the assessment of in vivo femoral bone strength. Over the past decades, a number of different FE models have been presented focusing on the effect of several methodological aspects, such as mesh type, material properties and loading conditions, on the precision and accuracy of these models. In this paper, a review of this work is presented. We conclude that moderate to good predictions can be made, especially when the models are tuned to specific loading scenarios. However, there is room for improvement when multiple loading conditions need to be evaluated. We hypothesize that including anisotropic material properties is the first target. As a proof of the concept, we demonstrate that the main orientation of the femoral bone structure can be calculated from clinical computed tomography scans. We hypothesize that this structural information can be used to estimate the anisotropic bone material properties, and that in the future this could potentially lead to a greater predictive value of FE models for femoral bone strength.

scholarly journals Buckling of a coated elastic half-space when the coating and substrate have similar material properties

2015 ◽  
Vol 471 (2178) ◽  
pp. 20140979 ◽  
Author(s):  
Y. B. Fu ◽  
P. Ciarletta
Keyword(s):  
Numerical Simulations ◽  
Material Properties ◽  
Deformation Gradient ◽  
Critical Value ◽  
Elastic Half Space ◽  
Similar Material ◽  
Fully Nonlinear ◽  
Shear Moduli ◽  
Subcritical Regime ◽  
Post Buckling

This study investigates the buckling of a uni-axially compressed neo-Hookean thin film bonded to a neo-Hookean substrate. Previous studies have shown that the elastic bifurcation is supercritical if r ≡ μ f / μ s >1.74 and subcritical if r <1.74, where μ f and μ s are the shear moduli of the film and substrate, respectively. Moreover, existing numerical simulations of the fully nonlinear post-buckling behaviour have all been focused on the regime r >1.74. In this paper, we consider instead a subset of the regime r <1.74, namely when r is close to unity. Four near-critical regimes are considered. In particular, it is shown that, when r >1 and the stretch is greater than the critical stretch (the subcritical regime), there exists a localized solution that arises as the limit of modulated periodic solutions with increasingly longer and longer decaying tails. The evolution of each modulated periodic solution is followed as r is decreased, and it is found that there exists a critical value of r at which the deformation gradient develops a discontinuity and the solution becomes a static shock. The semi-analytical results presented could help future numerical simulations of the fully nonlinear post-buckling behaviour.

Analysis and Prediction of Surface Integrity in Machining: A Review

2014 ◽  
Vol 610 ◽  
pp. 1002-1020 ◽  
Author(s):  
Yuan Gao ◽  
Xin Huang ◽  
Ming Jie Lin ◽  
Zheng Guo Wang ◽  
Rong Lei Sun
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Residual Stresses ◽  
Surface Integrity ◽  
Material Properties ◽  
Cutting Parameters ◽  
Mechanical Parameters ◽  
Factors Affecting ◽  
Grain Size And Shape

Surface integrity is widely used for evaluating the quality of machined components. It has a set of various parameters which can be grouped as: (a) topography parameters such as surface roughness, textures and waviness (b) mechanical parameters such as residual stresses and hardness, and (c) metallurgical state such as microstructure, phase transformation, grain size and shape, inclusions etc. Surface roughness and residual stresses are among the most significant parameters of surface integrity, so that it is worth investigating them particularly. Many factors affect the surface integrity of machined components, including cutting parameters, tool parameters, material properties and vibrations. We can make prediction and optimization for surface integrity by taking advantage of these factors. This paper reviews previous studies and gives a comprehensive summary of surface integrity in the following order: introduction of surface integrity, main parameters of surface integrity, factors affecting surface integrity, prediction and optimization for surface integrity.

Thermal Stress Analysis Based on Equivalent Age of Heterogeneous Mass Concrete

2013 ◽  
Vol 353-356 ◽  
pp. 3256-3262
Author(s):  
Pei Fang Su ◽  
Xing Li Lu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stress ◽  
Material Properties ◽  
Simulation Method ◽  
Temperature History ◽  
Mass Concrete ◽  
Mechanical Parameters ◽  
Equivalent Age ◽  
Fem Method ◽  
Calculation Procedures

In order to analysis thermal stress of mass concrete accurately, material properties of mass concrete are studied by numerical simulation method, and the equivalent age is introduced to describe the mechanical properties of concrete. The calculation models of concrete mechanical parameters are summarized, and then the calculation procedures are established on the basis of equivalent age. In this way, the temperature and temperature history are considered in these models. Meanwhile, the governing equation and computer program of the thermal stress based on the equivalent age are developed. The comparison of the numerical example using proposed method and conventional FEM method shows that the proposed method performs more adaptable and accurate.

An Improved Alternating Active-Phase Algorithm for Multi-Material Topology Optimization Problems

2014 ◽  
Vol 635-637 ◽  
pp. 105-111 ◽  
Author(s):  
Ming Tao Cui ◽  
Hong Fang Chen
Keyword(s):  
Topology Optimization ◽  
Optimization Problems ◽  
Active Phase ◽  
Optimality Criteria ◽  
Numerical Examples ◽  
Original Algorithm ◽  
Minimum Compliance ◽  
Object Based ◽  
The Mathematical Model ◽  
Improved Algorithm

For the multi-material topology optimization problems which take structural minimum compliance as the object, based on the weight function and optimality criteria, an improvement to the original alternating active-phase algorithm is achieved in establishing and calculating the mathematical model of multi-material topology optimization problems. Simulations of numerical examples are implemented respectively by the improved alternating active-phase algorithm and the original algorithm. It can be found that the minimum compliance obtained by the improved algorithm is generally lower than that obtained by the original algorithm in each numerical example, whereupon the feasibility and efficiency of the improved algorithm are manifested.

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