Dynamic Analysis Step-by-Step

1998 ◽  
Vol 120 (08) ◽  
pp. 61-62
Author(s):  
Yi Sug Kwon

This article discusses about engineers who are relying on mechanical simulations to improve their understanding of loading and operating conditions with high-rise escalators gain in popularity. To model an escalator design’s steps for dynamic analysis, LG engineers simplified the mechanical system by applying the drive directly to the upper terminal gear and the driving pulley without the motor. To model an escalator’s continuous elastic handrail, LG engineers divided it into 127 discrete rigid bodies, resulting in a total of 381 independent degrees of freedom. Two friction contact elements for each handrail body are applied to prevent rotational motion of the handrail. LG Industrial Systems managers decided to expand the number of engineers at the company with access to the simulation model. They assigned LG engineers to work with Computer Aided Design Software, Inc. (CADSI), of Coralville, Iowa analysts to develop a front end to DADS that simplifies the process of developing a custom escalator model.

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.


Author(s):  
Felicitas Pielsticker ◽  
Ingo Witzke ◽  
Amelie Vogler

AbstractDigital media have become increasingly important in recent years and can offer new possibilities for mathematics education in elementary schools. From our point of view, geometry and geometric objects seem to be suitable for the use of computer-aided design software in mathematics classes. Based on the example of Tinkercad, the use of CAD software — a new and challenging context in elementary schools — is discussed within the approach of domains of subjective experience and the Toulmin model. An empirical study examined the influence of Tinkercad on fourth-graders’ development of a model of a geometric solid and related reasoning processes in mathematics classes.


Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 685
Author(s):  
Manuel Prado-Velasco ◽  
Rafael Ortiz-Marín

The emergence of computer-aided design (CAD) has propelled the evolution of the sheet metal engineering field. Sheet metal design software tools include parameters associated to the part’s forming process during the pattern drawing calculation. Current methods avoid the calculation of a first pattern drawing of the flattened part’s neutral surface, independent of the forming process, leading to several methodological limitations. The study evaluates the reliability of the Computer Extended Descriptive Geometry (CeDG) approach to surpass those limitations. Three study cases that cover a significative range of sheet metal systems are defined and the associated solid models and patterns’ drawings are computed through Geogebra-based CeDG and two selected CAD tools (Solid Edge 2020, LogiTRACE v14), with the aim of comparing their reliability and accuracy. Our results pointed to several methodological lacks in LogiTRACE and Solid Edge that prevented to solve properly several study cases. In opposition, the novel CeDG approach for the computer parametric modeling of 3D geometric systems overcame those limitations so that all models could be built and flattened with accuracy and without methodological limitations. As additional conclusion, the success of CeDG suggests the necessity to recover the relevance of descriptive geometry as a key core in graphic engineering.


2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Andrew Johnson ◽  
Xianwen Kong ◽  
James Ritchie

The determination of workspace is an essential step in the development of parallel manipulators. By extending the virtual-chain (VC) approach to the type synthesis of parallel manipulators, this technical brief proposes a VC approach to the workspace analysis of parallel manipulators. This method is first outlined before being illustrated by the production of a three-dimensional (3D) computer-aided-design (CAD) model of a 3-RPS parallel manipulator and evaluating it for the workspace of the manipulator. Here, R, P and S denote revolute, prismatic and spherical joints respectively. The VC represents the motion capability of moving platform of a manipulator and is shown to be very useful in the production of a graphical representation of the workspace. Using this approach, the link interferences and certain transmission indices can be easily taken into consideration in determining the workspace of a parallel manipulator.


Author(s):  
A.O. KHARCHENKO ◽  
A.A. KHARCHENKO

The article presents the results of analysis and theoretical research in the direction of improving equipment for internal threading of parts in a flexible automated production. Methods for assessing the flexibility and readjustability of equipment are considered, which can be used as the basis for the developed methodology for the synthesis of technological elements of modules in conditions of computer-aided design. It is proposed to consider the technological system of the flexible manufacturing module (FMM) of threading, as a system in which transitions from state to state occur under the action of the simplest flows with the parameters of the transition probabilities of a continuous Markov chain. The developed mathematical model, which describes the states of a FMM, taking into account the readjustment of its technological elements, makes it possible to reflect the influence on the operation of the module of the parameters of applications for the changeover of processing modes, a tool, a power threading head, basic elements of a machine tool, a device, a loading device. The structure of the model and the labeled graph of the states of the system can be improved as the number of parameters and characteristics is refined. The solution of the resulting system of equations of final probabilities using the normalization condition allows for given (or experimentally obtained) intensities of arrival and service of changeover requests for FMM of threading, to obtain the values of the probability of non-changeover operation, as well as the probabilities of finding the system in an inoperative state due to the corresponding changeovers. For complete information and an objective assessment of the preferred option for use in FMS conditions, it is also necessary to take into account the stochastic processes occurring in the system under real operating conditions.


1986 ◽  
Vol 39 (9) ◽  
pp. 1345-1349 ◽  
Author(s):  
Dell K. Allen ◽  
W. Van Twelves

The importance of computer-aided design (CAD) has not been fully appreciated as it relates to computer integrated manufacturing (CIM). The CAD product definition model can provide essential information for many down-stream production, estimating, tooling, and quality assurance functions in the CIM environment. However, the product definition model may be inaccurate or incomplete, thus causing incomplete communication with possible scrap, re-work, and missed production deadlines. Other problems are related to the fact that many of our expert designers are retiring and taking their expertise with them. Merely being able to make 2D or 3D drawings on a CAD workstation does not make its operator a designer. A knowledge of production processes, tolerances, surface finish, and material selection is needed to supplement a designers knowledge of user needs, product functional requirements, operating conditions, cost, quality, and reliability targets. One of the most promising methods for providing timely and accurate information to the designer on an “as-needed” basis is through the use of expert design systems. Such systems promise to bridge the knowledge gap between CAD and CAM and help to incorporate these functions into the overall CIM environment.


1970 ◽  
Vol 1 (1) ◽  
Author(s):  
Y. M. A. Khalifa ◽  
D. H. Horrocks

An investigation into the application of Genetic Algorithms (GA) for the design of electronic analog circuits is presented in this paper. In this paper an investigation of the use of genetic algorithms into the problem of analog circuits design is presented. In a single design stage, circuits are produced that satisfy specific frequency response specifications using circuit structures that are unrestricted and with component values that are chosen from a set of preferred values. The extra degrees of freedom resulting from unbounded circuit structures create a huge search space. It is shown in this paper that Genetic Algorithms can be successfully used to search this space. The application chosen is a LC all pass ladder filter circuit design.Key Words: Computer-Aided Design, Analog Circuits, Artificial Intelligence.


2015 ◽  
Vol 764-765 ◽  
pp. 757-761 ◽  
Author(s):  
Yunn Lin Hwang ◽  
Jung Kuang Cheng ◽  
Van Thuan Truong

This paper presents simulation of multibody manufacturing systems with the support of numerical tools. The dynamic and cybernetic characteristics of driving system are discussed. Simple prototype models of robot arm and machine tool’s driving system are quickly established in Computer Aided Design (CAD) software inwhich the whole specification of material, inertia and so on are involved. The prototypes therefore are simulated in RecurDyn- a Computer Aided Engineering (CAE) software. The models are driven by controllers built in Matlab/Simulink via co-simulation. The results are suitable with theory and able to exploied for expansion of complexly effective factors. The research indicates that dynamic analysis and control could be done via numerical method instead of directly dynamic equation creation for multibody manufacturing systems.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Boyoung Kim ◽  
Minyong Choi ◽  
Seung-Woo Son ◽  
Deokwon Yun ◽  
Sukjune Yoon

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.


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