Direct modifications of tetrahedral meshes

2020 ◽  
Vol 37 (9) ◽  
pp. 3361-3385
Author(s):  
YuFei Guo ◽  
YongQing Hai ◽  
JianFei Liu
Keyword(s):  
Computer Aided Design ◽  
Tetrahedral Mesh ◽  
Surface Mesh ◽  
Content Type ◽  
Modification Method ◽  
Final Design ◽  
Ball Packing ◽  
Aided Design ◽  
Remeshing Algorithm ◽  
Packing Method

Purpose During the industrial design process, a product is usually modified and analyzed repeatedly until reaching the final design. Modifying the model and regenerating a mesh for every update during this process is very time consuming. To improve efficiency, it is necessary to circumvent the computer-aided design modeling stage when possible and directly modify the meshes to save valuable time. The purpose of this paper is to develop a method for mesh modifications. Design/methodology/approach In contrast to existing studies, which focus on one or a class of modifications, this paper comprehensively studies mesh union, mesh gluing, mesh cutting and mesh partitioning. To improve the efficiency of the method, the paper presents a fast and effective surface mesh remeshing algorithm based on a ball-packing method and controls the remeshing regions with a size field. Findings Examples and results show that the proposed mesh modification method is efficient and effective. The proposed method can be also applied to meshes with different material properties, which is very different with previous work that is only suitable for the meshes with same material property. Originality/value This paper proposes an efficient and comprehensive tetrahedral mesh modification method, through which engineers can directly modify meshes instead of models and save time.

The generation of adaptive assembly from predicting change propagation

2015 ◽  
Vol 35 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Hu Qiao ◽  
Rong Mo ◽  
Ying Xiang
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Original Method ◽  
Change Propagation ◽  
Assembly Model ◽  
Practical Application ◽  
Content Type ◽  
Design Structure ◽  
Aided Design ◽  
Practical Implications

Purpose – The purpose of this paper is to establish an adaptive assembly, to realize the adaptive changing of the models and to improve the flexibility and reliability of assembly change. For a three-dimensional (3D) computer-aided design (CAD) assembly in a changing process, there are two practical problems. One is delivering parameters’ information not smoothly. The other one is to easily destroy an assembly structure. Design/methodology/approach – The paper establishes associated parameters design structure matrix of related parts, and predicts possible propagation paths of the parameters. Based on the predicted path, structured storage is made for the affected parameters, tolerance range and the calculation relations. The study combines structured path information and all constrained assemblies to build the adaptive assembly, proposes an adaptive change algorithm for assembly changing and discusses the extendibility of the adaptive assembly. Findings – The approach would improve the flexibility and reliability of assembly change and be applied to different CAD platform. Practical implications – The examples illustrate the construction and adaptive behavior of the assembly and verify the feasibility and reasonability of the adaptive assembly in practical application. Originality/value – The adaptive assembly model proposed in the paper is an original method to assembly change. And compared with other methods, good results have been obtained.

Animal orthosis fabrication with additive manufacturing – a case study of custom orthosis for chicken

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wiktoria Maria Wojnarowska ◽  
Jakub Najowicz ◽  
Tomasz Piecuch ◽  
Michał Sochacki ◽  
Dawid Pijanka ◽  
...  
Keyword(s):  
Veterinary Medicine ◽  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Fused Deposition ◽  
Secondary Objective ◽  
Traditional Manufacturing ◽  
Aided Design

Purpose Chicken orthoses that cover the ankle joint area are not commercially available. Therefore, the main purpose of this study is to fabricate a customised temporary Ankle–Foot Orthosis (AFO) for a chicken with a twisted ankle using computer-aided design (CAD) and three-dimensional (3D) printing. The secondary objective of the paper is to present the specific application of Additive Manufacturing (AM) in veterinary medicine. Design/methodology/approach The design process was based on multiple sketches, photos and measurements that were provided by the owner of the animal. The 3D model of the orthosis was made with Autodesk Fusion 360, while the prototype was fabricated using fused deposition modelling (FDM). Evaluation of the AFO was performed using the finite element method. Findings The work resulted in a functional 3D printed AFO for chicken. It was found that the orthosis made with AM provides satisfactory stiffen and a good fit. It was concluded that AM is suitable for custom bird AFO fabrication and, in some respects, is superior to traditional manufacturing methods. It was also concluded that the presented procedure can be applied in other veterinary cases and to other animal species and other parts of their body. AM provides veterinary with a powerful tool for the production of well-fitted and durable orthoses for animals. Research limitations/implications The study does not include the chicken's opinion on the comfort or fit of the manufactured AFO due to communication issues. Evaluation of the final prototype was done by the researchers and the animal owner. Originality/value No evidence was found in the literature on the use of AM for chicken orthosis, so this study is the first to describe such an application of AM. In addition, the study demonstrates the value of AM in veterinary medicine, especially in the production of devices such as orthoses.

Computer-aided design of a dielectric insert supporting uniformity of fast microwave heating

2018 ◽  
Vol 37 (6) ◽  
pp. 1958-1968 ◽  
Author(s):  
Ethan M. Moon ◽  
Vadim V. Yakovlev
Keyword(s):  
Microwave Heating ◽  
Complex Permittivity ◽  
Computer Aided Design ◽  
Heating Time ◽  
Geometrical Parameters ◽  
Heating Rates ◽  
Content Type ◽  
Design Variables ◽  
Processed Material ◽  
Aided Design

PurposeThis paper aims to introduce and illustrate a computational technique capable of determining the geometry and complex permittivity of a supplementary dielectric insert making distributions of microwave-induced dissipated power within the processed material as uniform as possible.Design/methodology/approachThe proposed technique is based on a 3D electromagnetic model of the cavity containing both the processed material and the insert. Optimization problem is formulated for design variables (geometrical and material parameters of the insert) identified from computational tests and an objective function (the relative standard deviation [RSD]) introduced as a metric of the field uniformity. Numerical inversion is performed with the method of sequential quadratic programming.FindingsFunctionality of the procedure is illustrated by synthesis of a dielectric insert in an applicator for microwave fixation. Optimization is completed for four design variables (two geometrical parameters, dielectric constant and the loss factor of the insert) with 1,000 points in the database. The best three optimal solutions provide RSD approximately 20 per cent, whereas for the patterns corresponding to all 1,000 non-optimized (randomly chosen) sets of design variables this metric is in the interval from 27 to 136 per cent with the average of 78 per cent.Research limitations/implicationsAs microwave thermal processing is intrinsically inhomogeneous and the heating time is not a part of the underlying model, the procedure is able to lead only to a certain degree of closeness to uniformity and is intended for applications with high heating rates. The initial phase of computational identification of design variables and their bounds is therefore very important and may pre-condition the “quality” of the optimal solution. The technique may work more efficiently in combination with advanced optimization techniques dealing with “smart” (rather than random) generation of the data; for the use with more general microwave heating processes characterized by lower heating rates, the technique has to use the metric of non-uniformity involving temperature and heating time.Practical implicationsWhile the procedure can be used for computer-aided design (CAD) of microwave applicators, a related practical limitation may emerge from the fact that the material with particular complex permittivity (determined in the course of optimization) may not exist. In such cases, the procedure can be rerun for the constant values of material parameters of the available medium mostly close to the optimal ones to tune geometrical parameters of the insert. Special manufacturing techniques capable of producing a material with required complex permittivity also may be a practical option here.Originality/valueNon-uniformity of microwave heating remains a key challenge in the design of many practical applicators. This paper suggests a concept of a practical CAD and outlines corresponding computational procedure that could be used for designing a range of applied systems with high heating rates.

Vision-force guided precise robotic assembly for 2.5D components in a semistructured environment

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Boyoung Kim ◽  
Minyong Choi ◽  
Seung-Woo Son ◽  
Deokwon Yun ◽  
Sukjune Yoon
Keyword(s):  
Computer Aided Design ◽  
Degrees Of Freedom ◽  
Printed Circuit Board ◽  
Force Sensor ◽  
Circuit Board ◽  
Robotic Assembly ◽  
Ccd Cameras ◽  
Content Type ◽  
3 Dimensional ◽  
Aided Design

Purpose Many manufacturing sites require precision assembly. Particularly, similar to cell phones, assembly at the sub-mm scale is not easy, even for humans. In addition, the system should assemble each part with adequate force and avoid breaking the circuits with excessive force. The purpose of this study is to assemble high precision components with relatively reasonable vision devices compared to previous studies. Design/methodology/approach This paper presents a vision-force guided precise assembly system using a force sensor and two charge coupled device (CCD) cameras without an expensive 3-dimensional (3D) sensor or computer-aided design model. The system accurately estimates 6 degrees-of-freedom (DOF) poses from a 2D image in real time and assembles parts with the proper force. Findings In this experiment, three connectors are assembled on a printed circuit board. This system obtains high accuracy under 1 mm and 1 degree error, which shows that this system is effective. Originality/value This is a new method for sub-mm assembly using only two CCD cameras and one force sensor.

Parametric geometry model design of a wingsuit

2020 ◽  
Vol 32 (5) ◽  
pp. 691-705
Author(s):  
Nazanin Ansari ◽  
Sybille Krzywinski
Keyword(s):  
Computer Aided Design ◽  
Early Stage ◽  
Three Dimensional ◽  
Production Costs ◽  
Process Chain ◽  
Content Type ◽  
Geometry Model ◽  
Computer Aided ◽  
2D Pattern ◽  
Aided Design

PurposeThis paper aims to introduce a process chain spanning from scanned data to computer-aided engineering and further required simulations up to the subsequent production. This approach has the potential to reduce production costs and accelerate the procedure.Design/methodology/approachA parametric computer-aided design (CAD) model of the flyer wearing a wingsuit is created enabling easy changes in its posture and the wingsuit geometry. The objective is to track the influence of geometry changes in a timely manner for following simulation scenarios.FindingsAt the final stage, the two-dimensional (2D) pattern cuts were derived from the developed three-dimensional (3D) wingsuit, and the results were compared with the conventional ones used in the first stages of the wingsuit development.Originality/valueProposing a virtual development process chain is challenging; apart from the fact that the CAD construction of a wingsuit flyer – in itself posing a complicated task – is required at a very early stage of the procedure.

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.

scholarly journals Additively manufactured textiles and parametric modelling by generative algorithms in orthopaedic applications

2020 ◽  
Vol 26 (5) ◽  
pp. 827-834 ◽  
Author(s):  
Vito Ricotta ◽  
Robert Ian Campbell ◽  
Tommaso Ingrassia ◽  
Vincenzo Nigrelli
Keyword(s):  
Computer Aided Design ◽  
Selective Laser Sintering ◽  
Flexible Structure ◽  
Parametric Modelling ◽  
Content Type ◽  
Cad Modelling ◽  
Generative Algorithms ◽  
Application Fields ◽  
Aided Design ◽  
Design And Production

Purpose The purpose of this paper is to implement a new process aimed at the design and production of orthopaedic devices fully manufacturable by additive manufacturing (AM). In this context, the use of generative algorithms for parametric modelling of additively manufactured textiles (AMTs) also has been investigated, and new modelling solutions have been proposed. Design/methodology/approach A new method for the design of customised elbow orthoses has been implemented. In particular, to better customise the elbow orthosis, a generative algorithm for parametric modelling and creation of a flexible structure, typical of an AMT, has been developed. Findings To test the developed modelling algorithm, a case study based on the design and production of an elbow orthosis made by selective laser sintering was investigated. The obtained results have demonstrated that the implemented algorithm overcomes many drawbacks typical of the traditional computer aided design (CAD) modelling approaches. The parametric CAD model of the orthosis obtained through the new approach is characterised by a flexible structure with no deformations or mismatches and has been effectively used to produce the prototype through AM technologies. Originality/value The obtained results present innovative elements of originality in the CAD modelling sector, which can contribute to solving problems related to modelling for AM in different application fields.

Direct slicing of T-spline surfaces for additive manufacturing

2018 ◽  
Vol 24 (4) ◽  
pp. 709-721 ◽  
Author(s):  
Jiawei Feng ◽  
Jianzhong Fu ◽  
Zhiwei Lin ◽  
Ce Shang ◽  
Bin Li
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Content Type ◽  
Geometrical Properties ◽  
Direct Slicing ◽  
Spline Surface ◽  
Spline Surfaces ◽  
Complex Models ◽  
Aided Design ◽  
Design And Manufacture

Purpose T-spline is the latest powerful modeling tool in the field of computer-aided design. It has all the merits of non-uniform rational B-spline (NURBS) whilst resolving some flaws in it. This work applies T-spline surfaces to additive manufacturing (AM). Most current AM products are based on Stereolithograph models. It is a kind of discrete polyhedron model with huge amounts of data and some inherent defects. T-spline offers a better choice for the design and manufacture of complex models. Design/methodology/approach In this paper, a direct slicing algorithm of T-spline surfaces for AM is proposed. Initially, a T-spline surface is designed in commercial software and saved as a T-spline mesh file. Then, a numerical method is used to directly calculate all the slicing points on the surface. To achieve higher manufacturing efficiency, an adaptive slicing algorithm is applied according to the geometrical properties of the T-spline surface. Findings Experimental results indicate that this algorithm is effective and reliable. The quality of AM can be enhanced at both the designing and slicing stages. Originality/value The T-spline and direct slicing algorithm discussed here will be a powerful supplement to current technologies in AM.

Space claim analysis for addressing maintenance of key components in complex products

2017 ◽  
Vol 37 (1) ◽  
pp. 71-83 ◽  
Author(s):  
Andre Diogo Moscheto ◽  
Carlos Cziulik ◽  
Simão Marcon Junior ◽  
Marcos Sulevis
Keyword(s):  
Product Development ◽  
Computer Aided Design ◽  
Theory And Practice ◽  
Product Development Process ◽  
Design Development ◽  
Content Type ◽  
Cad Systems ◽  
New Information ◽  
Aided Design ◽  
Maintenance Personnel

Purpose The purpose of this paper is to provide a new approach involving guidelines and supporting techniques that guarantees all needed space for appropriate product maintenance. Design/methodology/approach The approach is based on two major areas: field survey to understand how maintainability parameter is applied and converge theory and practice into a systematic space claim method using computer-aided design (CAD) systems to assure proper maintenance procedures at design stages. Findings Case studies from a truck industry conducted following the proposed approach contrast the savings that can be achieved by using a proper space claim for aftermarket needs against an unsuitable level of participation by maintenance personnel during the design development. Research limitations/implications This approach is highly dependent on maintenance experts with suitable skills on CAD systems. Practical implications Products developed according to the approach envisaged can result in following aspects: lower repair time, better maintenance procedures on key components, easier preventive maintenance, less need for special tools, more ergonomic design, better communication between design and service engineers, simplicity and less complex training. Social implications Further research on maintainability will provide new information on how to apply this parameter on product development process (PDP), so design teams can better understand and address this relevant issue. The proposed method has been introduced in the PDP of a major multinational automotive company. Originality/value A new process is presented, considering the protection of needed spaces for maintenance procedures throughout the PDP, diverging to other studies that only propose analysis addressing maintainability at singular point in time during the product development. In just one case study presented, savings of US$1.3m were achieved by applying this space claim approach.

A method for common design structure discovery in assembly models using information from multiple sources

2016 ◽  
Vol 36 (3) ◽  
pp. 274-294 ◽  
Author(s):  
Jie Zhang ◽  
Mi Zuo ◽  
Pan Wang ◽  
Jian-feng Yu ◽  
Yuan Li
Keyword(s):  
Computer Aided Design ◽  
Frequent Subgraph Mining ◽  
Multiple Sources ◽  
Content Type ◽  
Design Structure ◽  
Design Cycle ◽  
Speed Up ◽  
Discovery Method ◽  
Aided Design ◽  
Assembly Models

Purpose Design is a time-consuming process for mechanical production. Some design structures frequently occur in different products and can be shared by multiple assembly models. Thus, identifying these structures and adding them to a design knowledge library significantly speed up the design process. Most studies addressing this issue have traditionally focused on part models and have not extended to assembly models. This paper aims to find a method for common design structure discovery in assembly models. Design/methodology/approach Computer-aided design models have a great deal of valuable information defined by different designers in the design stages, especially the assembly models, which are actually carriers of information from multiple sources. In this paper, an approach for discovering a common design structure in assembly models is proposed by comparing information from multiple sources. Assembly models are first represented as attribute connection graphs (ACGs), in which we mainly consider topological information and various attributes of parts and connections. Then, we apply a K-means clustering method based on a similarity analysis of different attributes to classify the parts and connections and transform ACGs of assemblies into type code graphs (TCGs). After this, a discovery algorithm that improves upon fast frequent subgraph mining is used to identify common design structures in assemblies. Findings A new method was developed for discovering common design structures in assembly models, considering the similarity of information from multiple sources and allowing some differences in the details to keep both commonalities and individualities of common design structures. Practical implications Experiments show that the proposed method is efficient and can produce a reasonable result. Originality/value This discovery method helps designers find common design structures from different assembly models and shorten the design cycle. It is an effective approach to build a knowledge library for product design that can shorten the design cycle.

Sign in / Sign up

Export Citation Format

Share Document