• Title/Summary/Keyword: Integration problems

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Application of the explicit time integration finite element method to quasi-static metal forming problems (금속 성형 공정의 준정적 변형 예측을 위한 외연적 시간 적분 유한 요소법의 적용에 대한 연구)

  • Yoo, Y.H.;Yang, D.Y.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.12
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    • pp.53-63
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    • 1995
  • In the analysis of metal forming problems, the explicit time integration finite element method, which does not have convergence problems, is frequently used. The present work is to assess the applicability of the explicit time integration finite element method to quasi-static metal forming problems. Compressing analyses of thin-walled tubes and solid cylinders are performed with different loading velocities. The computed buckled profiles of thin walled tubes are compared with the theoretical and experimental ones and it is found that at sufficiently low loading velocity, the explicit time integration finite element method accurately predict quasi-static buckled profiles. When loading volocity is increased, the computed buckled profiles of thin-walled tubes are very sensitive to loading velocity however the computed profiles of solid cylinders are less sensitive to loading velocity. In orther words, the geometrically self-constrained specimens like solid cylinders are less sensitive to loading velocity than the geometrically unconstrained specimens like thin-walled tubes. As a result, it is found that the geometrically self-constrained problems which include the greater part of metal forming problems can be efficiently analyzed with loading velocity control technique.

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Development of three dimensional variable-node elements and their applications to multiscale problems (삼차원 다절점 유한요소의 개발과 멀티스케일 문제의 적용)

  • Lim, Jae-Hyuk;Sohn, Dong-Woo;Im, Se-Young
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.172-176
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    • 2008
  • In this paper, three dimensional linear conforming variable-finite elements are presented with the aid of a smoothed integration (a class of stabilized conforming nodal integration), for mnltiscale mechanics problems. These elements meet the desirable properties of an interpolation such as the Kronecker delta condition, the partition of unity condition and the positiveness of interpolation function. The necessary condition of linear exactness is fully relaxed by employing the smoothed integration, which renders us to meet the linear exactness in a straightforward manner. This novel element description extend the category of the conventional finite elements space to ration type function space and give the flexibility on the number of nodes of element which are fixed in the conventional finite elements. Several examples are provided to show the convergence and the accuracy of the proposed elements, and to demonstrate their potential with emphasis on the multiscale mechanics problems such as global/local analysis, nonmatching contact problems, and modeling of composite material with defects.

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A Study on Hybrid Database Integration Model for Product Data Management (PDM을 위한 하이브리드 데이터베이스 통합 모델에 관한 연구)

  • Lee, Kang-Chan;Lee, Sang;Yoo, Jung-Yeon;Lee, Kyu-Chul
    • The Journal of Society for e-Business Studies
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    • v.3 no.1
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    • pp.23-41
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    • 1998
  • In a centralized database system, all system components reside at a single platform. In recent years there has been a rapid trend toward the integration of information systems over multiple sites that are interconnected via a communication network, and users' needs are changed to integration of multiple information sites. Multi database System is one of solutions for integrating distributed heterogeneous databases. However the problems in multi database system are restriction in distributed environment support, limitation in integrating heterogeneous media type data, static integration, and data-only of integration. In order to solve these problems, we propose a hybrid database integration model, HyDIM. HyDIM is used for the integrating legacy multimedia data, adopting CORBA, MDS, and mediator. We demonstrate a prototype system far PDM application domain.

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Using Canadian Occupational Performance Measure - On the Effects of Sensory Integration Treatment to the Daily-Life Task Performance of a Child with a Cerebral Palsy (감각통합치료가 뇌성마비 아동의 일상생활 기능에 미치는 효과 - 캐나다 작업수행 측정을 이용하여 -)

  • Kwon, Boon-Jung;Park, Ji-Young
    • The Journal of Korean Academy of Sensory Integration
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    • v.1 no.1
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    • pp.53-59
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    • 2003
  • Objective : The objective of this case study is to search the effects of sensory integration treatment. First we have taken a child with a cerebral palsy and given him/her sensory integration treatment. Then, we intended to look into whether the child performed his daily-life tasks and how satisfactory the parents were with the treatment. Methods : We have chosen a child with a cerebral palsy and tested his sensory integration functions. Applying the 30 minutes-sensory integration treatment twenty times to the child, we compared the result of the treatment using Canadian Occupational Performance Measure. We counseled the parents of the child before and after the treatment. Results : We have rated the problems with the degrees of importance referring to the parents. Important problems include controlling eliminations, having meals, moving by self, interacting with peer groups, and performing delicate hand-movements. The score of the in the performance is 1.2 and the score of the degree in the satisfaction is 1.4 compared with the total score. Conclusion : We have concluded that the sensory integration treatment has the effective result to the daily-life task performances of a child with a cerebral palsy, a kind of sensory integration dysfunction and satisfies the child's parents after this case study.

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A novel two sub-stepping implicit time integration algorithm for structural dynamics

  • Yasamani, K.;Mohammadzadeh, S.
    • Earthquakes and Structures
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    • v.13 no.3
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    • pp.279-288
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    • 2017
  • Having the ability to keep on yielding stable solutions in problems involving high potential of instability, composite time integration methods have become very popular among scientists. These methods try to split a time step into multiple sub-steps so that each sub-step can be solved using different time integration methods with different behaviors. This paper proposes a new composite time integration in which a time step is divided into two sub-steps; the first sub-step is solved using the well-known Newmark method and the second sub-step is solved using Simpson's Rule of integration. An unconditional stability region is determined for the constant parameters to be chosen from. Also accuracy analysis is perform on the proposed method and proved that minor period elongation as well as a reasonable amount of numerical dissipation is produced in the responses obtained by the proposed method. Finally, in order to provide a practical assessment of the method, several benchmark problems are solved using the proposed method.

Integrated equations of motion for direct integration methods

  • Chang, Shuenn-Yih
    • Structural Engineering and Mechanics
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    • v.13 no.5
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    • pp.569-589
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    • 2002
  • In performing the dynamic analysis, the step size used in a step-by-step integration method might be much smaller than that required by the accuracy consideration in order to capture the rapid chances of dynamic loading or to eliminate the linearization errors. It was first found by Chen and Robinson that these difficulties might be overcome by integrating the equations of motion with respect to time once. A further study of this technique is conducted herein. This include the theoretical evaluation and comparison of the capability to capture the rapid changes of dynamic loading if using the constant average acceleration method and its integral form and the exploration of the superiority of the time integration to reduce the linearization error. In addition, its advantage in the solution of the impact problems or the wave propagation problems is also numerically demonstrated. It seems that this time integration technique can be applicable to all the currently available direct integration methods.

Case Analysis and Strategic Impiications for Prod uct and Service Integration (제품과 서비스 통합을 위한 사례분석과 전략대응방안)

  • Kwon, Suhn-Beom
    • Journal of Information Technology Services
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    • v.8 no.1
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    • pp.217-229
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    • 2009
  • Manufacturers have recently faced such problems like limitation of product differentiation, product commoditization and increased service request level from customers, Some manufacturers have responded the problems by introducing new business model, 'product and service integrated offering', which integrate product and its services as a bundled package, This article introduces innovative 7 cases of 'product and service integrated offering', and provides case analyses : types, methods, purposes, and risks of integration, The result of analysis, 4 strategic directions for product and service integration offering, could help manufacturers to adopt and build their model successfully, Further research topics are field survey with meaningful sample size including Business-to-Consumer and finding new causal relationships among variables like characteristics of industry, product, Integration, interaction between provider and customer, A development of design methodology on how to plan and develope a sound product service integration is the second next step for the research.

Implementation of Embedded Web Server and XML Web Services for Intelligent Building System (지능형 빌딩 시스템을 위한 임베디드 웹 서버와 XML 웹 서비스의 구현)

  • Kim, Tae-Kook;Chang, Hyeong-Jun;Park, Gwi-Tae
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.12
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    • pp.1167-1172
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    • 2007
  • The existing building control and automation systems which have been applied to buildings are provided by many different vendors and each vendor has its own proprietary protocol. There are many problems in system integration since those building control and automation systems belong to each vendor. Also, the problems of cost and space increase, due to the usage of personal computers as the control servers of DDC(Direct Digital Control) in each facility. Those problems mentioned above can be effectively resolved by using XML Web Services and Embedded Web Server. Embedded Web Server and XML Web Services are technologies emerging out of the IT industries and there are many researches to apply them into many fields. In this paper, Embedded Web Server and XML Web Services are proposed to be used in building control and automation system to resolve problems in building system integration.

A fast precise integration method for structural dynamics problems

  • Gao, Q.;Wu, F.;Zhang, H.W.;Zhong, W.X.;Howson, W.P.;Williams, F.W.
    • Structural Engineering and Mechanics
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    • v.43 no.1
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    • pp.1-13
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    • 2012
  • A fast precise integration method (FPIM) is proposed for solving structural dynamics problems. It is based on the original precise integration method (PIM) that utilizes the sparse nature of the system matrices and especially the physical features found in structural dynamics problems. A physical interpretation of the matrix exponential is given, which leads to an efficient algorithm for both its evaluation and subsequently the solution of large-scale structural dynamics problems. The proposed algorithm is accurate, efficient and requires less computer storage than previous techniques.

Development of a New Discontinuous Time Integration Method for Transient Analysis of Impact Phenomena (충격해석을 위한 새로운 불연속 시간적분법의 개발)

  • 조진연;김승조
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.407-412
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    • 1998
  • In this work, a new time integration method is proposed using the generalized derivative concept to simulate the dynamic phenomena having sudden constraint occurring in dynamic contact/impact problems. By the adoption of the generalized derivative concept and jump assumption, discontinuity can be incorporated in time integration and as a result, the algorithm does not need any other special consideration of jumps in dynamic field variables due to sudden constraint like dynamic contact-release conditions. To observe the characteristics of the proposed time integration method, the stability and convergence analyses are carried out. In numerical tests, several dynamic contact/impact problems are analyzed by straightforward application of the proposed time integration method with the exterior penalty method.

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