scholarly journals In Silico Optimization of Femoral Fixator Position and Configuration by Parametric CAD Model

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2326
Author(s):  
Nikola Korunovic ◽  
Dragan Marinkovic ◽  
Miroslav Trajanovic ◽  
Manfred Zehn ◽  
Milorad Mitkovic ◽  
...  
Keyword(s):  
Finite Element ◽  
Structural Optimization ◽  
Computer Aided Design ◽  
Bone Fractures ◽  
Element Model ◽  
Long Bone ◽  
Design Parameters ◽  
Cad Model ◽  
Cad Models ◽  
Aided Design

Structural analysis, based on the finite element method, and structural optimization, can help surgery planning or decrease the probability of fixator failure during bone healing. Structural optimization implies the creation of many finite element model instances, usually built using a computer-aided design (CAD) model of the bone-fixator assembly. The three most important features of such CAD models are: parameterization, robustness and bidirectional associativity with finite elements (FE) models. Their significance increases with the increase in the complexity of the modeled fixator. The aim of this study was to define an automated procedure for the configuration and placement of fixators used in the treatment of long bone fractures. Automated and robust positioning of the selfdynamisable internal fixator on the femur was achieved and sensitivity analysis of fixator stress on the change of major design parameters was performed. The application of the proposed methodology is considered to be beneficial in the preparation of CAD models for automated structural optimization procedures used in long bone fixation.

Automated Finite Element Model Mesh Updating Scheme Applicable to Mistuning Analysis

2014 ◽  
Author(s):  
Alexander A. Kaszynski ◽  
Joseph A. Beck ◽  
Jeffrey M. Brown
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
User Involvement ◽  
Element Model ◽  
Cad Model ◽  
Data Set ◽  
Optical Scanner ◽  
Wide Range ◽  
Cad Models ◽  
Scan Data

Advancement of optical geometric measurement hardware has enabled the construction of accurate 3D tessellated models for a wide range of turbomachinery components. These tessellated models can be reverse-engineered into computer-aided design (CAD) models and input into grid generation software for finite element analyses. However, generating a CAD model from scan data is a time consuming and cumbersome process requiring significant user-involvement for even a single model. While it is possible to generate finite element models (FEMs) directly from tessellated data, current direct-grid methods produce unstructured grids that can introduce fictitious, numerical mistuning in these models, obscuring geometric mistuning. Nonetheless, as-measured scan data captured in a structured grid is essential for accurate geometric mistuning analyses, provided the tessellated scan data can be rapidly and accurately transformed into a FEM. This paper outlines and demonstrates an approach for rapidly generating structured FEMs for a population of integrally bladed rotors (IBRs) without requiring the arduous task of generating a CAD model for each as-measured IBR. This is accomplished by morphing the structured mesh of a nominal model to the tessellated data set collected from an optical scanner. It is shown that the fidelity and structure of these FEMs can be utilized for accurate mistuning analyses.

scholarly journals Automatized Evaluation of Students’ CAD Models

2021 ◽  
Vol 11 (4) ◽  
pp. 145
Author(s):  
Nenad Bojcetic ◽  
Filip Valjak ◽  
Dragan Zezelj ◽  
Tomislav Martinec
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Computer Application ◽  
Test Cases ◽  
Cad Model ◽  
Computer Solution ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

The article describes an attempt to address the automatized evaluation of student three-dimensional (3D) computer-aided design (CAD) models. The driving idea was conceptualized under the restraints of the COVID pandemic, driven by the problem of evaluating a large number of student 3D CAD models. The described computer solution can be implemented using any CAD computer application that supports customization. Test cases showed that the proposed solution was valid and could be used to evaluate many students’ 3D CAD models. The computer solution can also be used to help students to better understand how to create a 3D CAD model, thereby complying with the requirements of particular teachers.

Vertical tail FEA with a CAD/CAE based multidisciplinary process

2018 ◽  
Vol 90 (4) ◽  
pp. 652-658
Author(s):  
Péter Deák
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Tail Length ◽  
Element Model ◽  
Point Of View ◽  
Content Type ◽  
Nodal Displacements ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Aided Design

Purpose The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view. Design/methodology/approach The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model. Findings The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented. Practical implications The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD. Originality/value The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.

Geometric Measurement of Wear in Tibial Inserts Through an Autonomous Reconstruction of the Original Surface

2011 ◽  
Author(s):  
Christopher B. Knowlton ◽  
George Hanson ◽  
Diego Orozco ◽  
Michel P. Laurent ◽  
Markus A. Wimmer
Keyword(s):  
Computer Aided Design ◽  
Design Parameters ◽  
Limiting Factor ◽  
Total Knee Replacements ◽  
Knee Replacements ◽  
Cad Models ◽  
Total Knee ◽  
Aided Design ◽  
Geometric Measurement ◽  
Worn Surfaces

Wear of the polyethylene tibial components in total knee replacements remains a limiting factor of implant life. Studies have used coordinate measuring machines (CMM) to estimate volumetric wear in retrieved components. This technique requires knowledge of the original pre-worn surfaces. Pre-worn surfaces have been successfully approximated in literature by nominal computer-aided design (CAD) models or, more commonly, size-matched unused inserts [1,2]. However, models and drawings of implants are proprietary, and many design parameters can have large tolerances. Unworn components are costly, often unattainable for obsolete implants and subject to deviation between batches.

Toward Effective Mechanical Design Reuse: CAD Model Retrieval Based on General and Partial Shapes

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Min Li ◽  
Y. F. Zhang ◽  
J. Y. H. Fuh ◽  
Z. M. Qiu
Keyword(s):  
Computer Aided Design ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Cad Model ◽  
Model Retrieval ◽  
Cad Models ◽  
Feature Based ◽  
Novel Method ◽  
Aided Design ◽  
Model Similarity

In product design, a large proportion of three-dimensional (3D) computer-aided design (CAD) models can be reused to facilitate future product development due to their similarities in function and shape. This paper presents a novel method that incorporates modeling knowledge into CAD model similarity assessment to improve the effectiveness of reuse-oriented retrieval. First, knowledge extraction is performed on archived feature-based CAD models to construct feature dependency directed acyclic graph (FDAG). Second, based on the FDAG subgraph decomposition, two useful component partitioning approaches are developed to extract simplified essential shapes and meaningful subparts from CAD models. Third, the extracted shapes and their FDAG subgraphs are indexed. Finally, the indexed shapes that are similar to user-sketched queries are retrieved to reuse, and FDAG information of the retrieved shapes is provided as redesign suggestions. Experimental results suggest that the incorporation of modeling knowledge greatly facilitates CAD model retrieval and reuse. Algorithm evaluations also show the presented method outperforms other 3D retrieval methods.

Effect of Intramedullary Nailing Patterns On Interfragmentary Strain in a Mouse Femur Fracture: a Parametric Finite Element Analysis

2021 ◽  
Author(s):  
Gregory Lowen ◽  
Katherine Garrett ◽  
Moore-Lotridge Stephanie ◽  
Sasidhar Uppuganti ◽  
Scott A. Guelcher ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Healing ◽  
Bone Repair ◽  
Bone Fractures ◽  
Fracture Site ◽  
Fracture Repair ◽  
Long Bone ◽  
Design Parameters ◽  
Element Analysis

Abstract Delayed long bone fracture healing and nonunion continue to be a significant socioeconomic burden. While mechanical stimulation is known to be an important determinant of the bone repair process, understanding how the magnitude, mode, and commencement of interfragmentary strain (IFS) affect fracture healing can guide new therapeutic strategies to prevent delayed healing or non-union. Mouse models provide a means to investigate the molecular and cellular aspects of fracture repair, yet there is only one commercially available, clinically-relevant, locking intramedullary nail (IMN) currently available for studying long bone fractures in rodents. Having access to alternative IMNs would allow a variety of mechanical environments at the fracture site to be evaluated, and the purpose of this proof-of-concept finite element analysis study is to identify which IMN design parameters have the largest impact on IFS in a murine transverse femoral osteotomy model. Using the dimensions of the clinically relevant IMN as a guide, the nail material, distance between interlocking screws, and clearance between the nail and endosteal surface were varied between simulations. Of these parameters, changing the nail material from stainless steel (SS) to polyetheretherketone (PEEK) had the largest impact on IFS. Reducing the distance between the proximal and distal interlocking screws substantially affected IFS only when nail modulus was low. Therefore, IMNs with low modulus (e.g., PEEK) can be used alongside commercially available SS nails to investigate the effect of initial IFS or stability on fracture healing with respect to different biological conditions of repair in rodents.

Characterization of Tissue Scaffolds Fabricated by Rapid Prototyping Techniques Aided by Finite Element Analysis

2006 ◽  
Author(s):  
Andrew R. Thoreson ◽  
James J. Stone ◽  
Kurtis L. Langner ◽  
Jay Norton ◽  
Bor Z. Jang
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Cartilage Regeneration ◽  
Element Model ◽  
Tissue Scaffolds ◽  
Design Parameters ◽  
Element Analysis ◽  
Apparent Modulus ◽  
Wide Range

Numerous techniques for fabricating tissue engineering scaffolds have been proposed by researchers covering many disciplines. While literature regarding properties and efficacy of scaffolds having a single set of design parameters is abundant, characterization studies of scaffold structures encompassing a wide range of design parameters are limited. A Precision Extrusion Deposition (PED) system was developed for fabricating poly-ε-caprolactone (PCL) tissue scaffolds having interconnected pores suitable for cartilage regeneration. Scaffold structures fabricated with three-dimensional printing methods are periodic and are readily modeled using Computer Aided Design (CAD) software. Design parameters of periodic scaffold architectures were identified and incorporated into CAD models with design parameters over the practical processing range represented. Solid models were imported into a finite element model simulating compression loading. Model deformation results were used to identify apparent modulus of elasticity of the structure. PCL scaffold specimens with design parameters within the modeled range were fabricated and subjected to compression testing to physically characterize scaffold modulus. Results of physical testing and finite element models were compared to determine effectiveness of the method.

scholarly journals Computerized Generation and Finite Element Stress Analysis of Endodontic Rotary Files

2021 ◽  
Vol 11 (10) ◽  
pp. 4329
Author(s):  
Victor Roda-Casanova ◽  
Álvaro Zubizarreta-Macho ◽  
Francisco Sanchez-Marin ◽  
Óscar Alonso Ezpeleta ◽  
Alberto Albaladejo Martínez ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computer Aided Design ◽  
Element Model ◽  
Transverse Load ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Element Analysis ◽  
Design Skills ◽  
Von Mises

Introduction: The finite element method has been extensively used to analyze the mechanical behavior of endodontic rotary files under bending and torsional conditions. This methodology requires elevated computer-aided design skills to reproduce the geometry of the endodontic file, and also mathematical knowledge to perform the finite element analysis. In this study, an automated procedure is proposed for the computerized generation and finite element analysis of endodontic rotary files under bending and torsional conditions. Methods: An endodontic rotary file with a 25mm total length, 0.25mm at the tip, 1.20mm at 16mm from the tip, 2mm pitch and squared cross section was generated using the proposed procedure and submitted for analysis under bending and torsional conditions by clamping the last 3mm of the endodontic rotary file and applying a transverse load of 0.1N and a torsional moment of 0.3N·cm. Results: The results of the finite element analyses showed a maximum von Mises stress of 398MPa resulting from the bending analysis and a maximum von Mises stress of 843MPa resulting from the torsional analysis, both of which are next to the encastre point. Conclusions: The automated procedure allows an accurate description of the geometry of the endodontic file to be obtained based on its design parameters as well as a finite element model of the endodontic file from the previously generated geometry.

Interactive Freeform Clay Modeling Supported by 3D Scanning and Robot Machining

2004 ◽  
Author(s):  
Y. Song ◽  
J. S. M. Vergeest ◽  
T. Wiegers
Keyword(s):  
Computer Aided Design ◽  
Virtual Prototyping ◽  
Cad Model ◽  
Physical Clay ◽  
3 Dimensional ◽  
Clay Model ◽  
Mesh Model ◽  
Robot Machining ◽  
Cad Models ◽  
Aided Design

Effective and efficient prototyping is always a challenging topic in design and prototyping. For this purpose, an interactive prototyping center is developed in this paper. The proposed technique is based on a synthesis of clay modeling, 3-Dimensional (3-D) scanning, robot machining and advanced geometric tools. Using 3-D scanning and reverse engineering techniques, a physical clay model is digitized to a Computer Aided Design (CAD) model by mesh representation. By advanced geometric tools, the mesh model can be changed easily following the user’s ideas. Those changes can be reflected to the clay model by robot machining. Furthermore, manual modifications on the existing clay model also can be added to the CAD model by 3-D scanning. For robot machining, a method based on 3-D scanning is used to calibrate the workpiece coordinate and the fixtures. Based on this system, virtual prototyping and physical prototyping can be achieved simultaneously. Solid or surface CAD models can be constructed directly from the mesh model after the prototyping stage. Experiments were made to demonstrate the effectiveness of the prototyping system. The possible applications in industrial product design are described as well.

Graph-Based Simplification of Feature-Based Three-Dimensional Computer-Aided Design Models for Preserving Connectivity

2015 ◽  
Vol 15 (3) ◽  
Author(s):  
Soonjo Kwon ◽  
Byung Chul Kim ◽  
Duhwan Mun ◽  
Soonhung Han
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Evaluation Metrics ◽  
Prototype System ◽  
Cad Model ◽  
3D Cad ◽  
Computer Aided ◽  
Cad Models ◽  
Feature Based ◽  
Aided Design

The required level of detail (LOD) of a three-dimensional computer-aided design (3D CAD) model differs according to its purpose. It is therefore important that users are able to simplify a highly complex 3D CAD model and create a low-complexity one. The simplification of a 3D CAD model requires the application of a simplification operation and evaluation metrics for the geometric elements of the 3D CAD model. The evaluation metrics are used to select those elements that should be removed. The simplification operation removes selected elements in order to simplify the 3D CAD model. In this paper, we propose the graph-based simplification of feature-based 3D CAD models using a method that preserves connectivity. First, new evaluation metrics that consider the discrimination priority among several simplification criteria are proposed. Second, a graph-based refined simplification operation that prevents the separation of a feature-based 3D CAD model into multiple volumes is proposed. Finally, we verify the proposed method by implementing a prototype system and performing simplification experiments using feature-based 3D CAD models.

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