Parametric Solid Modeling Research Articles

Parametric Solid Models of the At-Term Uterus From Magnetic Resonance Images.

Birthing mechanics are poorly understood, though many injuries during childbirth are mechanical, like fetal and maternal tissue damage. Several biomechanical simulation models of parturition have been proposed to investigate birth, but many do not include the uterus. Additionally, most solid models rely on segmenting anatomical structures from clinical images to generate patient geometry, which can be time-consuming. This work presents two new parametric solid modeling methods for generating patient-specific, at-term uterine three-dimensional geometry. Building from an established method of modeling the sagittal uterine shape, this work improves the uterine coronal shape, especially where the fetal head joins the lower uterine wall. Solid models of the uterus and cervix were built from five at-term patients' magnetic resonance imaging (MRI) sets. Using anatomy measurements from MRI-segmented models, two parametric models were created-one that employs an averaged coronal uterine shape and one with multiple axial measurements of the coronal uterus. Through finite element analysis, the two new parametric methods were compared to the MRI-segmented high-fidelity method and a previously published elliptical low-fidelity method. A clear improvement in the at-term uterine shape was found using the two new parametric methods, and agreement in principal Lagrange strain directions was observed across all modeling methods. These methods provide an effective and efficient way to generate three-dimensional solid models of patient-specific maternal uterine anatomy, advancing possibilities for future research in computational birthing biomechanics.

МОДЕЛИРОВАНИЕ ТЕЛ С ЭЛЛИПСОИДНЫМИ ПОРАМИ В ВЕКТОРНО-ПАРАМЕТРИЧЕСКОМ ПРЕДСТАВЛЕНИИ

The article discusses the problem of geometric modeling of ellipsoidal pores with the possibility of using this model under arbitrary deformation conditions. A method is used for constructing a threeparameter body with boundary surfaces based on Hermite interpolation functions using parametric solid modeling technology. Solving this problem will make it possible to obtain a geometric model of deformable porous objects for studying existing and for creating new materials that have the required properties for the development of new products and processes

Advancing formative assessment in MCAD education: The visual analytics of parametric feature-based solid models

Advancing formative assessment in MCAD education is an important but difficult problem. Success in this endeavor requires feature-based MCAD model assessment to consider the quality of a model from various viewpoints. That includes the absolute criteria that are associated with technical domain knowledge and also criteria related to model deficiencies. For the latter, this entails assessing the results of wrong or inappropriately applied system commands, and of partial or entire modeling strategies. Here, an approach that combines the perceptual abilities, creativity, and domain knowledge of the human user with the computational power of current desktop computing has great potential to contribute to solving the problem. The aim of the current paper is two-fold. Firstly, it presents a novel approach to analyzing feature-based characteristics of MCAD models, an approach that is aimed at advancing formative assessment in the educational context. This approach is based on visual analytics and efforts to combine visualization, human factors, and data analytics. Secondly, it reports on the technical architecture and concrete implementation of a newly developed visualization environment for a software tool to enable and put into practice this novel MCAD model assessment approach. The development of this new visualization environment is based on an advanced visualization pipeline that employs radial visualization, while supporting dedicated user interaction techniques to facilitate analytical processes.

Design of conformal lattice structures using the volumetric distance field based on parametric solid models

Purpose The purpose of this paper is to describe a novel design method to construct lattice structure computational models composed of a set of unit cells including simple cubic, body-centered cubic, face-centered cubic, diamond cubic and octet cubic unit cell. Design/methodology/approach In this paper, the authors introduce a new implicit design algorithm based on the computation of volumetric distance field (VDF). All the geometric components including lattice core structure and outer skin are represented with VDFs in a given design domain. This enables computationally efficient design of a computational model for an arbitrarily complex lattice structure. In addition, the authors propose a hybrid method based on the VDF and parametric solid models to construct a conformal lattice structure, which is oriented in accordance with the geometric form of the exterior surface. This method enables the authors to design highly complex lattice structure, computational models, in a consistent design framework irrespective of the complexity in geometric representations without sacrificing accuracy and efficiency. Findings Experimental results are shown for a variety of geometries to validate the proposed design method along with illustrative several lattice structure prototypes built by additive manufacturing techniques. Originality/value This method enables the authors to design highly complex lattice structure, computational models, in a consistent design framework irrespective of the complexity in geometric representations without sacrificing accuracy and efficiency.

Procedure of creating three-dimensional solid models of tool electrodes for electrochemical pulse machining of gas turbine engine parts in CAD-systems with their parametric coupling with software module profiling

This work is dedicated to the creation of parametric solid models of tool electrodes based on the results of the calculation of the previously created software module. The developed technique will facilitate the solution of the problem of technological preparation of the operation of electrochemical machining (ECM) of a gas turbine emgine copressor. In this case, the solution could be obtained by simulations in several iterations and would completely preclude all machine work and mechanical hand-operated development of electrodes. The technique is based on a mathematical model of electrochemical shaping of a gas turbine engine airfoil using pulse current. In developing the model the electric comductivity and temperature were taken to be constant, the current output depended only on the current density, the anode and cathode overvoltage was determined by the polarization curves, the peculiarities of the anode process dynamics were considered by the current density and the parameters of the hydrodynamic conditions were taken to be optimal. A software module was developed in the course of developing the procedure. The module developed provides easy implementation of a mathematical model of profiling tool electrodes in ECM. Electronic models of electrode profiles that could be used in producing control software for machining electrode profiles on CNC machines are the end result of such simulation.

Design and simulation of an optimized electrothermal microactuator with Z-shaped beams

The displacement of the central shuttle of a Z-shape chevron actuator can be calculated using a developed approach from other authors. Who demonstrated that the actuators with this geometry offer a larger displacement compared with V-shape actuators. Z-shape offers a larger stiffness and output force for the case of only one arm. This paper is focused on the optimization of the Z-shaped beams of a chevron actuator of eight beams, which seeks to increase the previously described response. The structure is designed in parametric solid modeling 3D software Autodesk Inventor, and simulated by finite element method in Ansys 15.0. These simulations were implemented considering several modifications on the length of the Z-shaped beams in order to choose the most appropriate length. The electric potential applied in all cases was from 0.2 V up to 5 V. The Z-shape length of the arms for the case of the optimized Z-shape actuator increases the shuttle’s displacement in approximately 50% compared to V-shape actuator, and 38% compare to the original Z-shape. Analytical adjusted approach is extremely matched with the simulations results. Length of the Z-shape beam is the determinant factor of the displacement. The low stiffness of the optimized Z-shape actuator (89% lower than the original V-shape and 58% compared to Z-shape) can allow its use as load sensor.

Procedure of creating three-dimensional solid models of tool electrodes for electrochemical pulse machining of gas turbine engine parts in CAD-systems with their parametric coupling with software module profiling

This work is dedicated to the creation of parametric solid models of tool electrodes based on the results of the calculation of the previously created software module. The developed technique will facilitate the solution of the problem of technological preparation of the operation of electrochemical machining (ECM) of a gas turbine emgine copressor. In this case, the solution could be obtained by simulations in several iterations and would completely preclude all machine work and mechanical hand-operated development of electrodes. The technique is based on a mathematical model of electrochemical shaping of a gas turbine engine airfoil using pulse current. In developing the model the electric comductivity and temperature were taken to be constant, the current output depended only on the current density, the anode and cathode overvoltage was determined by the polarization curves, the peculiarities of the anode process dynamics were considered by the current density and the parameters of the hydrodynamic conditions were taken to be optimal. A software module was developed in the course of developing the procedure. The module developed provides easy implementation of a mathematical model of profiling tool electrodes in ECM. Electronic models of electrode profiles that could be used in producing control software for machining electrode profiles on CNC machines are the end result of such simulation.

Automatic shape adaptation for parametric solid models

Adaptation, as is well known, plays a fundamental role in Case-Based Design. However, after decades of efforts, automatic adaptation approach is still rare. In common design works, the first thing one will usually do is choosing a start-up model (a candidate model) of moderate complexity based on a simple query model possessing primary design constraints. To enable the candidate model to smartly adapt its shape to that of the query model according to the embedded constraints, a novel automatic shape adaptation approach is proposed in this paper. First, to determine the corresponding faces between two non-preregistered models as relevant elements, a shape frame concept and its quantitative descriptor are defined. Second, to unify the representation of seemingly different but inherently consistent dimensions, a promotion method is adopted. Third, based on the corresponding faces and the promoted dimension representation, the corresponding dimensions between the two parametric solid models are identified. Finally, the parametric information is smoothly transferred from the query model to the candidate model as design constraints, and the shape of the candidate model is automatically adapted to the query model. Besides that, a prototype system is also implemented to verify the effectiveness of the automatic shape adaptation approach.

A Pre-Processing Method of ProCAST Based on Pro/E and HyperMesh

In order to improve the quality of ProCAST casting simulation, a pre-processing method is proposed based on Pro/E software and HyperMesh software. In this paper, Pro/E software parametric solid modeling and HyperMesh finite element meshing functions were used, a ProCAST pre-processing method is proposed based on Pro/E and HyperMesh software, it overcomes the meshing problems of ProCAST casting simulation and achieves the connections among Pro/E, HyperMesh and ProCAST. Compared with the basic ProCAST casting simulation meshing module, the Pro/E and HyperMesh pre-processing method improves the accuracy of modeling and meshing, the method is easy to realize with high accurancy.

High Speed ​​Gear Parametric Modeling and Dynamic Analysis

In order to solve high-speed gear parametric solid modeling technology, improve the accuracy of design calculations gear, based the involute of inclined cylindrical gears tooth profile formed the basic principles, in the UG software system and through VB programming using UG’s parameter expression to modeling, constructing parameterized solid model of locomotive traction gear and the modeling of transmission. Analyzing and calculating with ADAMS software that the dynamic performance of gear system, provides the basis for speed ​​gear strength and parameter optimization.

Structural analysis of Scorbot-ER Vu plus industrial robot manipulator

Robots are required to operate in different environmental conditions facing varieties of workspace interactions. Scorbot-ER Vu plus robot is a real industrial robot. Robot is designed and analysed for existing condition. Computer-Aided Engineering methods used effectively in the design process since the robot design has various parameters. Structural analyses are aimed to compute the deformations, internal forces, stresses, support reactions, accelerations and stability of the object. This paper deals with structural analysis of Scorbot-ER Vu plus industrial robot in which the integrated engineering methods are employed. The robot manipulator parametric solid models were constructed using Pro/ENGINEER. During the design process, the different structural modifications are made according to the results of various engineering analysis. ABAQUS was used to analyse the structures of the robot. Nodal analysis of the robot is also reviewed for two mode positions using the ABAQUS program. Finally, accurate model of robot manipulator was developed.

Modeling and Modal Analysis of Less-Teeth Gear Shaft

As the less-teeth gear has the less-teeth, the bigger helix angle and the more contact ratio etc. The research of dynamic meshing characteristics makes focus, and modal analysis is the basis of dynamic analysis. In order to get the modal analysis characteristics: firstly the parametric solid modeling is realized through the software of MATLAB and PRO/E; secondly multistage inherent frequencies and mode shapes are achieved by the finite element software of ANSYS Workbench.

Integrated CAD/CAE/CAM System for Scorbot-ER Vu Plus Industrial Robot Manipulator

Robots are required to operate in different environmental conditions facing varieties of end-effector to perform the workspace interactions. This paper deals with integrated CAD/CAE/CAM system for SCORBOT-ER Vu plus Industrial robot manipulator. The DH (DenavitHartenberg) coordinate transformation method was used to perform the robot position analysis. The robot manipulator parametric solid models were constructed using Pro/ENGINEER (Pro/E). Pro/Mechanica was used to simulate the dynamic simulation and working space, CATIA was used to implement the cutting simulation, and the prototype was manufactured using a CNC milling machine. Finally, a CAD/CAE/CAM integrated system for a robot manipulator was developed. This integrated system not only promotes automation capabilities for robot manipulator production, but also simplifies the CAD/CAE/CAM process for a robot manipulator.

Analysis for Wedge Falling-Proof Brake Assembly of Lifter with Converter Oxygen Lance

Designing wedge falling-proof brake assembly of the lifter to protect the converter oxygen lance and other equipments. This paper briefly introduces the design principle. Pro/Engineer-based parametric solid modeling for virtual assembly of the falling-proof brake assembly, and then motion simulation, the working process of the wedge falling-proof brake assembly demonstrated through the animation demonstration, so the simulation is accurate and clear; at the same time falling distance is derived from the rope broken to the lifter locked through mechanical analysis, and putting forward the measures to reduce falling distance of brake at last.

Precision Analysis of Reconstructed Aluminum Alloy Handle

In order to carry out the error analyses of the aluminum alloy in reverse engineering, Mastercam was used to create three-dimensional (3D) parametric solid models and automatically generate NC program files. By using the generated NC program, a simulating is processed on a milling machine. The surface of the obtained product 1 was immediately scanned by a laser scanner. Using the obtained results from the laser scanner, the three-dimensional models were created in Geomagic Studio. Reanalysis of the three dimensional models, product 2 can be obtained. Finally, Error analysis was carried out by comparing the 3D scan data with the original design models. The current research demonstrates that error analysis by the present method is feasible. However, since aluminum was selected as the processing material, the scanned data is not satisfactory; contrast error is greater after reverse engineering.

Finite Element Contact Analysis of Locomotive Traction Gears

The parametric solid models and assemble model are built in Pro/Engineer software system on the base of basic parameters of locomotive traction gears. The dedendum transition curves of teeth are fit by inputting the accurate coordinates of real curve of tooth that machined by gear hob after analyzing the envelopment processing of tooth. Assembling the driving and driven gears in Pro/Engineer system, and then the assemble model is imported into ANSYS software system, the settings of finite element analysis are defined, the finite element contact analysis of the driving and driven gears is done in ANSYS software. The accurate stress distributions of contact stress of teeth surfaces and the bending stress of dedendum of teeth are obtained base on the simulation calculations and post-processing in ANSYS. The calculation results are accurate compared with the real stress condition of teeth, so it can be the base of optimization design of gears for further research.

Finite Element Contact Analysis of Locomotive Traction Gears

The parametric solid models and assemble model are built in Pro/Engineer software system on the base of basic parameters of locomotive traction gears. The dedendum transition curves of teeth are fit by inputting the accurate coordinates of real curve of tooth that machined by gear hob after analyzing the envelopment processing of tooth. Assembling the driving and driven gears in Pro/Engineer system, and then the assemble model is imported into ANSYS software system, the settings of finite element analysis are defined, the finite element contact analysis of the driving and driven gears is done in ANSYS software. The accurate stress distributions of contact stress of teeth surfaces and the bending stress of dedendum of teeth are obtained base on the simulation calculations and post-processing in ANSYS. The calculation results are accurate compared with the real stress condition of teeth, so it can be the base of optimization design of gears for further research.

Development of a CAD Based Platform for Scorbot-ER Vu Industrial Robot Manipulator

Robots are required to operate at different environmental conditions facing varieties of end-effector to workspace interactions. During design stage, designer needs to verify the robots performance on various test conditions. Physical prototyping although is more desirable, may prove to be expensive and time consuming. Virtual prototyping can be used especially in the conceptual design stage in order to reduce the amount of physical testing that is required. Virtual prototyping of robots dynamic is one of the interesting fields where in the present day tools are used to simulate mechanical systems as a multi-body system with two or more rigid bodies imperfectly joined together having the possibility of relative moment between them. This paper discusses the application of Virtual Prototyping using CAD based software for SCORBOT-ER Vu robot. It is a 5-DOF of vertical articulated robot and all the joints are revolute. Initially, robot manipulator parametric solid models was created in Pro/ENGINEER (Pro/E), Pro/Mechanica was used to simulate the dynamic simulation and working space. Finally the program was tested in the real world, using the real robot.

The Design and Experiment of Oval Bevel Gear

Aiming at the complex design and analysis methods of noncircular bevel gear, combining the gear space engagement theory and the generating method of tooth profile, the profile generating process was seen as the pure rolling between the pitch line of virtual processing tool and pitch curve of oval bevel gear based on the virtual generating method. The blank parameters and relation equation between tool parameters and procedure parameters of generating method were deduced. General parametric solid models of oval bevel gear were founded. Based on experimental result of oval bevel gear transmission, the design profile of oval bevel gear which was obtained according to generating method was verified.

Development of Die Sets standard parts library based on Pro/E

The topic carries out development of die sets standard parts library according to “China Die & Mould Engineering Canon” .Parametric solid models are built based on Pro/E, the family table library of standard parts is established using the Family Table Function of Pro/E, the database library of parts is established by using Access, the Man-Machine interactive interface is designed by applying Python, the application program is developed with VC ++6.0 and Pro/Toolkit, so as to parametric die sets standard parts library system is established. The system has good man-machine interactive interface with strong features of interactive dialogue window, and it's easy for user to choose standard parts, to fetch the corresponding data from database according to the National Standard of the standard part, to build the corresponding 3D solid model of die sets standard parts automatically by the application program. The system could help user to complete the die design rapidly and improve the innovation design and efficient.