TOPOLOGY OPTIMIZATION OF LIGHTWEIGHT STRUCTURES WITH APPLICATION TO BONE SCAFFOLDS AND 3D PRINTED SHOES FOR DIABETICS

2022 ◽  
pp. 1-9
Author(s):  
Zhujiang Wang ◽  
Arun Srinivasa ◽  
J.N. Reddy ◽  
Adam Dubrowski
Keyword(s):  
Finite Element ◽  
Optimization Algorithm ◽  
Boundary Surface ◽  
3D Models ◽  
Truss Structures ◽  
Foot Pressure ◽  
Structure Generation ◽  
Lightweight Structures ◽  
Complex Topology ◽  
Lightweight Structure

Abstract An automatic complex topology lightweight structure generation method (ACTLSGM) is presented to automatically generate 3D models of lightweight truss structures with a boundary surface of any shape. The core idea of the ACTLSGM is to use the PIMesh, a mesh generation algorithm developed by the authors, to generate node distributions inside the object representing the boundary surface of the target complex topology structures; raw lightweight truss structures are then generated based on the node distributions; the resulting lightweight truss structure is then created by adjusting the radius of the raw truss structures using an optimization algorithm based on finite element truss analysis. The finite element analysis-based optimization algorithm can ensure the resulting structures satisfy the design requirements on stress distributions or stiffness. Three demos, including a lightweight structure for a cantilever beam, a femur bone scaffold, and a 3D shoe sole model with adaptive stiffness that can be used to adjust foot pressure distributions for patients with diabetic foot problems, are generated to demonstrate the performance of the ACTLSGM. The ACTLSGM is not limited to generating 3D models of medical devices, but can be applied in many other fields, including 3D printing infills and other fields where customized lightweight structures are required.

Design of the Lightweight Structure and its Mechanical Properties

2013 ◽  
Vol 461 ◽  
pp. 57-62
Author(s):  
Xiao Ting Jiang ◽  
Ce Guo ◽  
Xiu Yan Cao ◽  
Zhen Yu Lu
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Fiber Material ◽  
Element Analysis ◽  
Static Compression ◽  
Lightweight Structures ◽  
Carbon Fiber Material ◽  
The Finite Element Analysis ◽  
Lightweight Structure

Based on the microstructure of the cross-section of the beetle's elytra, a kind of bio-inspiredlightweight structure was designed and made by the carbon fiber material. The compressive andshear mechanical properties of the lightweight structures were studied with finite element method.In addition, quasi-static compression experiments of the structure samples were carried out. Theexperimental results and the finite element analysis results were compared and analyzed, whichproved the effectiveness of the finite element analysis.

scholarly journals Investigation of Energy-Absorbing Properties of a Bio-Inspired Structure

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 881
Author(s):  
Adrian Dubicki ◽  
Izabela Zglobicka ◽  
Krzysztof J. Kurzydłowski
Keyword(s):  
Absorption Capacity ◽  
Compression Tests ◽  
Element Analysis ◽  
Lightweight Structures ◽  
New Energy ◽  
Absorbing Material ◽  
Lightweight Structure ◽  
3D Printed ◽  
Deformation Force ◽  
Energy Absorbing

Numerous engineering applications require lightweight structures with excellent absorption capacity. The problem of obtaining such structures may be solved by nature and especially biological structures with such properties. The paper concerns an attempt to develop a new energy-absorbing material using a biomimetic approach. The lightweight structure investigated here is mimicking geometry of diatom shells, which are known to be optimized by nature in terms of the resistance to mechanical loading. The structures mimicking frustule of diatoms, retaining the similarity with the natural shell, were 3D printed and subjected to compression tests. As required, the bio-inspired structure deformed continuously with the increase in deformation force. Finite element analysis (FEA) was carried out to gain insight into the mechanism of damage of the samples mimicking diatoms shells. The experimental results showed a good agreement with the numerical results. The results are discussed in the context of further investigations which need to be conducted as well as possible applications in the energy absorbing structures.

COMPARATIVE ANALYSIS FOR THREE FIXTURES OF PAUWELLS-II BY THE BIOMECHANICAL FINITE ELEMENT METHOD

2019 ◽  
Vol 20 (01) ◽  
pp. 1950079
Author(s):  
MATTHEW JIAN-QIAO PENG ◽  
HONGWEN XU ◽  
HAI-YAN CHEN ◽  
XIANGYANG JU ◽  
YONG HU ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Femoral Shaft ◽  
3D Models ◽  
Procedure Time ◽  
Stable Fixation ◽  
Secondary Fracture ◽  
Solid Models ◽  
Acute Correction ◽  
Hip Screw

Little is known about why and how biomechanics govern the hypothesis that three-Lag-Screw (3LS) fixation is a preferred therapeutic technique. A series models of surgical internal-fixation for femoral neck fractures of Pauwells-II will be constructed by an innovative approach of finite element so as to determine the most stable fixation by comparison of their biomechanical performance. Seventeen sets of CT scanned femora were imported onto Mimics extracting 3D models; these specimens were transferred to Geomagic Studio for a simulative osteotomy and kyrtograph; then, they underwent UG to fit simulative solid models; three sorts of internal fixators were expressed virtually by Pro-Engineer. Processed by Hypermesh, all compartments were assembled onto three systems actually as “Dynamic hip screw (DHS), 3LS and DHS+LS”. Eventually, numerical models of Finite Elemental Analysis (FEA) were exported to AnSys for solution. Three models for fixtures of Pauwells-II were established, validated and analyzed with the following findings: Femoral-shaft stress for [Formula: see text](3LS) is the least; Internal-fixator stress (MPa) for [Formula: see text]; Integral stress (MPa) for [Formula: see text]; displacement of femoral head (mm) for a[Formula: see text](DHS+LS) = 0.735; displacement of femoral shaft (mm) for [Formula: see text]; and displacement of fixators for [Formula: see text]. Mechanical comparisons for other femoral parks are insignificantly different, and these data can be abstracted as follows: the stress of 3LS-system was checked to be the least, and an interfragmentary displacement of DHS+LS assemblages was assessed to be the least”. A 3LS-system should be recommended to clinically optimize a Pauwells-II facture; if treated by this therapeutic fixation, breakage of fixators or secondary fracture is supposed to occur rarely. The strength of this study is that it was performed by a computer-aided simulation, allowing for design of a preoperative strategy that could provide acute correction and decrease procedure time, without harming to humans or animals.

Modal Analyses of Deployable Truss Structures Based on Shape Memory Polymer Composites

2016 ◽  
Vol 08 (07) ◽  
pp. 1640009 ◽  
Author(s):  
Fengfeng Li ◽  
Liwu Liu ◽  
Xin Lan ◽  
Tong Wang ◽  
Xiangyu Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Shape Memory ◽  
Polymer Composites ◽  
Dynamic Properties ◽  
Low Cost ◽  
Shape Memory Polymer ◽  
Truss Structures ◽  
Modal Test ◽  
The Stability ◽  
Mechanical Devices

With large spatial deployable antennas used more widely, the stability of deployable antennas is attracting more attention. The form of the support structure is an important factor of the antenna’s natural frequency, which is essential to study to prevent the resonance. The deployable truss structures based on shape memory polymer composites (SMPCs) have made themselves feasible for their unique properties such as highly reliable, low-cost, light weight, and self-deployment without complex mechanical devices compared with conventional deployable masts. This study offers deliverables as follows: an establishment of three-longeron beam and three-longeron truss finite element models by using ABAQUS; calculation of natural frequencies and vibration modes; parameter studies for influence on their dynamic properties; manufacture of a three-longeron truss based on SMPC, and modal test of the three-longeron truss. The results show that modal test and finite element simulation fit well.

scholarly journals Characterizing material liberation of multi-material lightweight structures from shredding experiments and finite element simulations

2021 ◽  
Vol 172 ◽  
pp. 107142
Author(s):  
Magdalena Heibeck ◽  
Martin Rudolph ◽  
Niels Modler ◽  
Markus Reuter ◽  
Angelos Filippatos
Keyword(s):  
Finite Element ◽  
Finite Element Simulations ◽  
Lightweight Structures

DIGITAL FABRICATION AS A LEARNING MEDIA FOR LIGHTWEIGHT STRUCTURE WITH CASE STUDY OF SHELL STRUCTURE

MODUL ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 126-133
Author(s):  
Stephanus Evert Indrawan ◽  
LMF Purwanto
Keyword(s):  
Shell Structure ◽  
Laser Cutting ◽  
Digital Fabrication ◽  
Scalar Model ◽  
Structure System ◽  
Lightweight Structures ◽  
Digital Devices ◽  
Lightweight Structure ◽  
Realization Process

The lightweight structure system is an effort to optimize the structure to distribute the load efficiently. Unfortunately, students often have difficulty imagining the learning outcomes application in the real world when studying light structural systems. However, the use of the scalar model can still explain several essential aspects of a lightweight structural system, one of which is the effect of connection and formation of material components on the structural capability. Therefore, this paper aims to bridge the learning process by utilizing digital devices from the concept stage of structural modeling with the help of software (Rhinoceros, Grasshopper, and Kangaroo) to the realization process using laser cutting. The method used is a semi-experimental method that applies Hooke's law principle, which produces a shell structure system with a digital fabrication approach that utilizes a lightweight material, namely, corrugated paper board, as the primary material. This paper concludes that digital technology and digital fabrication processes can help students understand the concept of lightweight structures because they can use computer simulations, cut them using laser cutting, and assemble them in the field in a series of simultaneous processes. 

scholarly journals Comparative Analysis for Internal Fixations of Pauwels II by Biomechanical Finite Element Method

2019 ◽  
Vol 103 (9-10) ◽  
pp. 493-504
Author(s):  
Matthew Jian-Qiao Peng ◽  
Xiangyang Ju ◽  
Hai-Yan Chen ◽  
Bai Bo ◽  
XinXu Li
Keyword(s):  
Finite Element ◽  
South Carolina ◽  
Femoral Neck ◽  
Femoral Neck Fracture ◽  
3D Models ◽  
Secondary Fracture ◽  
Solid Models ◽  
Neck Fracture ◽  
Hip Screw ◽  
3D Solid

Purpose: A series models of surgical internal fixation for femoral neck fracture of Pauwels II will be constructed by an innovative approach of finite element so as to determine the most stable fixation by comparison of their biomechanical performance. Method: Seventeen specimens of proximal femurs scanned by computed tomography in Digital Imaging and Communications in Medicine (DICOM) format were input onto Mimics rebuilding 3D models; their stereolithography (STL) format dataset were imported into Geomagic Studio (3D Systems, Rock Hill, South Carolina) for simulative osteotomy and non-uniform rational basis spline kartograph; the generated IGS dataset were interacted by UG to fit simulative 3D-solid models; 3 sorts of internal fixators were expressed in 3D model by ProE (PTC, Boston, Connecticut) program virtually. Processed by HyperMesh (Altair, Troy, Michigan), all compartments (fracture model + internal immobilization) were assembled onto 3 systems actually as: Dynamic hip screw (DHS) / Lag screw (LS) / DHS+LS. Eventually, a numerical model of finite elemental analysis was exported to ANSYS for solution. Result: Three models of internal fixations for femoral neck fracture of Pauwels II were established and validated effectively, the stress and displacement of each internal pin were analyzed, the advantages of each surgical therapy for femoral neck fracture of Pauwels II were compared and demonstrated synthetically as: “The contact stress of 3-LS-system was checked to be the least; the interfragmentary displacement of DHS+1-LS assemblages was assessed to be the least.” Conclusion: 3-LS-system is recommended to be a clinical optimization for Pauwels II femoral neck facture, by this therapeutic fixation mechanically, breakage of fixators, or secondary fracture rarely occurs.

scholarly journals An evolutionary-based optimization algorithm for truss sizing design

2016 ◽  
Vol 38 (4) ◽  
pp. 307-317
Author(s):  
Pham Hoang Anh
Keyword(s):  
Local Search ◽  
Objective Function ◽  
Optimization Algorithm ◽  
Optimization Problems ◽  
Optimal Solution ◽  
The Other ◽  
Truss Structures ◽  
Benchmark Problems ◽  
Discrete Variables ◽  
Objective Functions

In this paper, the optimal sizing of truss structures is solved using a novel evolutionary-based optimization algorithm. The efficiency of the proposed method lies in the combination of global search and local search, in which the global move is applied for a set of random solutions whereas the local move is performed on the other solutions in the search population. Three truss sizing benchmark problems with discrete variables are used to examine the performance of the proposed algorithm. Objective functions of the optimization problems are minimum weights of the whole truss structures and constraints are stress in members and displacement at nodes. Here, the constraints and objective function are treated separately so that both function and constraint evaluations can be saved. The results show that the new algorithm can find optimal solution effectively and it is competitive with some recent metaheuristic algorithms in terms of number of structural analyses required.

scholarly journals Stiffness prediction for bolted moment-connections in cold-formed steel trusses

2020 ◽  
Vol 41 (1) ◽  
Author(s):  
Apai Benchaphong ◽  
Rattanasak Hongthong ◽  
Sutera Benchanukrom ◽  
Nirut Konkong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Method ◽  
Truss Structures ◽  
Rotational Stiffness ◽  
Element Analysis ◽  
Moment Connection ◽  
Rigid Connection ◽  
Cold Formed Steel ◽  
Steel Trusses

The purpose of this research was to study the behavior of cold-formed steel cantilever truss structures. A cantilever truss structure and bolt-moment connection were tested and verified by the 3D-finite element model. The verification results showed a good correlation between an experimental test and finite element analysis. An analytical method for elastic rotational stiffness of bolt-moment connection was proposed. The equation proposed in the analytical method was used to approximate the elastic rotational stiffness of the bolt group connection, and was also applied to the Richard-Abbott model for generating the nonlinear moment-rotation curve which modeled the semi-rigid connection stiffness. The 2D-finite element analysis was applied to study the behavior of the truss connection, caused by semi-rigid connection stiffness which caused a change of force to the truss elements. The results showed that the force in the structural members increased by between 13.62%-74.32% of the axial forces, and the bending moment decreased by between 33.05%-100%. These results strongly suggest that the semi-rigid connection between cold-formed steel cantilever truss structures should be considered in structural analysis to achieve optimum design, acknowledging this as the real behavior of the structure.

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