Similarity Search for Voxelized CAD Objects

Author(s):  
Hans-Peter Kriegel ◽  
Peer Kröger ◽  
Martin Pfeifle ◽  
Stefan Brecheisen ◽  
Marco Pötke ◽  
...  

Similarity search in database systems is becoming an increasingly important task in modern application domains such as multimedia, molecular biology, medical imaging, and many others. Especially for CAD (Computer-Aided Design), suitable similarity models and a clear representation of the results can help to reduce the cost of developing and producing new parts by maximizing the reuse of existing parts. In this chapter, we present different similarity models for voxelized CAD data based on space partitioning and data partitioning. Based on these similarity models, we introduce anindustrial prototype, called BOSS, which helps the user to get an overview over a set of CAD objects. BOSS allows the user to easily browse large data collections by graphically displaying the results of a hierarchical clustering algorithm. This representation is well suited for the evaluation of similarity models and to aid an industrial user searching for similar parts.

The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.


2021 ◽  
Vol 111 (2) ◽  
pp. 66-77
Author(s):  
M. Othmani ◽  
K. Zarbane ◽  
A. Chouaf

Purpose: The present work aims to investigate the effect of many infill patterns (rectilinear, line, grid, triangles, cubic, concentric, honeycomb, 3D honeycomb) and the infill density on the mechanical tensile strength of an Acrylonitrile Butadiene Styrene (ABS) test specimen manufactured numerically by FDM. Design/methodology/approach: Computer-Aided Design (CAD) software has been used to model the geometry and the mesostructure of the test specimens in a fully automatic manner from a G-code file by using a script. Then, a Numerical Design of Experiments (NDoE) has been carried out by using Taguchi method and the Analysis of Variance (ANOVA). The tensile behaviour of these numerical test specimens has been studied by the Finite Element Analysis (FEA). Findings: The FEA results showed that a maximal Ultimate Tensile Strength (UTS) was reached by using the ‘concentric’ infill pattern combined with an infill density of 30%. The results also show that the infill pattern and the infill density are significant factors. Research limitations/implications: The low infill densities of 20% and 30% that have already been used in many previous studies, we have also applied it in order to reduce the time of the simulations. Indeed, with high infill density, the simulations take a very excessive time. In an ongoing study, we predicted higher percentages. Practical implications: This study provided an important modelling tool for the design and manufacture of functional parts and helps the FDM practitioners and engineers to manufacture strong and lightweight FDM parts by choosing the optimal process parameters. Originality/value: This study elucidated the effect of various infill patterns on the tensile properties of the test specimens and applied for the first time a NDoE using numerical test specimens created by the mesostructured approach, which considerably minimized the cost of the experiments while obtaining an error of 6.8% between the numerical and the experimental values of the UTS.


2020 ◽  
pp. 030936462094829 ◽  
Author(s):  
Trevor Binedell ◽  
Eugene Meng ◽  
Karupppasamy Subburaj

Background: Upper limb, in particular forequarter amputations, require highly customised devices that are often expensive and underutilised. Objectives: The objective of this study was to design and develop a comfortable 3D-printed cosmetic forequarter prosthetic device, which was lightweight, cool to wear, had an elbow that could lock, matched the appearance of the contralateral arm and was completely free of metal for a specific user’s needs. Study Design: Device design. Technique: An iterative user-centred design approach was used for digitising, designing and developing a functional 3D-printed prosthetic arm for an acquired forequarter amputation, while optimising the fit and function after each prototype. Results: The cost of the final arm was 20% less expensive than a traditionally-made forequarter prostheses in Singapore. The Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) 2.0 survey was administered, with results indicating that the 3D-printed arm was preferred due to its overall effectiveness, accurate size, ease of use and suspension. However, durability had a lower score, and the weight of the arm was 100 g heavier than the user’s current prosthesis. The technique described resulted in a precise fitting and shaped forequarter prosthesis for the user. Using the user’s feedback in the iterations of the design resulted in improved QUEST survey results indicating the device was effective, easy to use, perceived as lighter and more secure than the user’s traditionally-made device. Conclusion: A fully customised cosmetic forequarter prosthesis was designed and developed using digital scanning, computer-aided design modelling and 3D printing for a specific user. These technologies enable new avenues for highly complex prosthetic design innovations.


Author(s):  
J C Rico ◽  
S Mateos ◽  
E Cuesta ◽  
C M Suárez

This paper presents a program for the automatic design of special tools developed under a CAD/CAM (computer aided design/manufacture) system. In particular, the special tools made with standard components have been considered. Since the design of these types of tools was essentially related to the selection of their components, this paper deals with this aspect, insisting upon the selection of those components directly related to the removal of material: the toolholders or cartridges and the inserts. To select these components it is necessary to take into account not only geometrical or technological rules but also economical ones, owing to the high amount of possible components they can select. Consideration of economical aspects required the formulation of the cost equation associated with the use of these types of tools, characterized because their cutting edges coincide with different cutting velocities. Likewise, consideration of economical aspects allows the selection of the optimum cutting conditions and the cutting components to take place at the same time. Some of the geometrical and technological parameters related to the selection of cutting components are automatically identified by the system through an automatic identification of the workpiece profile.


1995 ◽  
Vol 117 (2) ◽  
pp. 199-204 ◽  
Author(s):  
J. R. Wagner

The cost effective design of antilock brake systems for automobiles requires the use of computer aided design and analysis techniques, as well as traditional invehicle testing. An important consideration in the simulation of the vehicle and brake dynamics is the generation of the shear forces and aligning torques at the tire/road interface. Frequently, experimental tire data gathered over a limited number of road surfaces is extrapolated to test antilock brake systems on a variety of roads. However, this approach may lead to problems in correlating the simulated system performance with actual vehicle tests. In this study, nonlinear programming strategies are applied to an analytical tire model to facilitate the selection of system variables. The formulation of an optimization problem to determine these variables permits the generation of shear forces which correspond fairly well with the empirical data. Simulation results are presented and discussed for five road surfaces to indicate the overall performance of this technique.


Author(s):  
Tapoglou Nikolaos ◽  
Antoniadis Aristomenis

Gear hobbing is a common method of manufacturing high precision involute gears. The thorough knowledge of the developed cutting forces and the wear of the cutting tool are of great importance in order to produce helical and spur gears as they influence the cost of the manufacturing process and the quality of the produced gear. A novel simulation code called HOB3D was created in accordance with the above. This code can simulate the complex movements involved in gear hobbing with the best available accuracy, which is achieved by embedding the developed algorithm in a commercial computer aided design (CAD) environment. The simulation code calculates and exports the total cutting forces as well as the cutting forces in every cutting edge involved in the cutting process.


2020 ◽  
Vol 7 (2) ◽  
pp. 037-048
Author(s):  
T. A. Sheveleva ◽  

The article presents the history of the creation of computer-aided design systems, an overview of special programs and CAD systems for the kinematic study of mechanisms, as well as examples of the use of these programs in computer simulation of the movement of mechanisms. The urgency of this problem is determined by the need to perform synthesis and analysis of mechanisms that have found wide application in modern technology. The use of computer modeling for the kinematic study of mechanisms allows you to reduce the time for designing mechanisms, and with this the cost of the final product.


2007 ◽  
Vol 2 (3) ◽  
pp. 274-278 ◽  
Author(s):  
Dmitry Vlasenko ◽  
Roland Kasper

This paper introduces a new modular software approach combining symbolical and numerical methods for the simulation of the dynamics of mechanical systems. It is based on an exact, noniterative object-oriented algorithm, which is applicable to mechanisms with any joint type and any topology, including branches and kinematic loops. The simulation of big well-partitioned systems has complexity O(N), where N is the total number of simulated bodies. A new design software Virtual System Designer (VSD) integrates this method with the three-dimensional computer aided design tool Autodesk Inventor, which minimizes the cost of the development of models and the training of design engineers. The most time-expensive routine of the simulation process in VSD is the calculation of the accelerations of each body, which needs to find the roots of matrix equations. Accounting for the sparsity of matrices can significantly improve the numerical efficiency of the routine. The preprocessing module, developed using Maple software, performs the symbolic simplification of the matrix multiplication’s and QR decomposition’s procedures. The new coordinate projection method is demonstrated. The results of the simulation of the dynamics of a double insulator chain example show the method’s stability and effectiveness.


Author(s):  
F J Richardson

Success of the design process hinges on efficient communication between the various functions involved. Traditionally this communication has been ‘paper based’ with information passing between sales, design, production and manufacture to describe the complete history of the product. This complex interaction between the functions depends on the availability at each stage of the most up-to-date and accurate information. The paper based system has many shortcomings in this respect particularly the inability of the designer to assess interactively the effect of any changes he may make on the cost, delivery, quality and performance of the product. The use of computer aided design as a central part of the computer aided engineering system allows a company greatly to improve communications during a project by giving the engineer a way of providing accurate information more quickly to each adjacent function while receiving feedback on the effectiveness and suitability of the product in a fraction of the time.


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