• Title, Summary, Keyword: inverse limit

Search Result 86, Processing Time 0.032 seconds

EXPANSIVITY ON ORBITAL INVERSE LIMIT SYSTEMS

  • Chu, Hahng-Yun;Lee, Nankyung
    • Journal of the Chungcheong Mathematical Society
    • /
    • v.32 no.1
    • /
    • pp.157-164
    • /
    • 2019
  • In this article, we study expansiveness of the shift maps on orbital inverse limit spaces which consist of two cross bonding mappings. On orbital inverse limit systems, horizontal directions express inverse limit systems and vertical directions mean orbits based on horizontal axes. We characterize the c-expansiveness of functions on orbital spaces. We also prove that the c-expansiveness of the functions is equivalent to the expansiveness of the shift maps on orbital inverse limit spaces.

Determination of the Forming Limit Strain of Sheet Metal Using Inverse Quartic Curve Fitting (역4차식 곡선근사에 의한 판재 성형한계변형률의 결정)

  • Lee, J.S.;Kim, J.D.;Kim, H.J.
    • Transactions of Materials Processing
    • /
    • v.22 no.6
    • /
    • pp.328-333
    • /
    • 2013
  • The current study aims to determine the limit strains more accurately and reasonably when producing a forming limit curve (FLC) from experiments. The international standard ISO 12004-2 in its recent version (2008) states that the limit major strain should be determined by using the best-fit inverse second-order parabola through the experimental strain distribution. However, in cases where fracture does not occur at the center of the specimen, due to insufficient lubrication, the inverse parabola does not give a realistic fit because of its intrinsic symmetry in shape. In this study it is demonstrated that an inverse quartic function can give a much better fit than an inverse parabola in almost all FLC test samples showing asymmetric strain distributions. Using a quartic fit creates more reliable FLCs.

SOME SHADOWING PROPERTIES OF THE SHIFTS ON THE INVERSE LIMIT SPACES

  • Tsegmid, Nyamdavaa
    • Journal of the Chungcheong Mathematical Society
    • /
    • v.31 no.4
    • /
    • pp.461-466
    • /
    • 2018
  • $Let\;f:X{\rightarrow}X$ be a continuous surjection of a compact metric space X and let ${\sigma}_f:X_f{\rightarrow}X_f$ be the shift map on the inverse limit space $X_f$ constructed by f. We show that if a continuous surjective map f has some shadowing properties: the asymptotic average shadowing property, the average shadowing property, the two side limit shadowing property, then ${\sigma}_f$ also has the same properties.

DERIVED LIMITS OF INVERSE SYSTEMS OVER (PRE)ORDERED SETS

  • LEE, HONG-JAE;LEE, DAE-WOONG
    • Honam Mathematical Journal
    • /
    • v.22 no.1
    • /
    • pp.77-82
    • /
    • 2000
  • After considering an equivalence relation on a directed preordered set, we construct an isomorphism between derived limits of inverse systems indexed by the directed (pre)ordered sets.

  • PDF

VARIOUS SHADOWING PROPERTIES FOR INVERSE LIMIT SYSTEMS

  • Lee, Manseob
    • Journal of the Chungcheong Mathematical Society
    • /
    • v.29 no.4
    • /
    • pp.657-661
    • /
    • 2016
  • Let $f:X{\rightarrow}X$ be a continuous surjection of a compact metric space and let ($X_f,{\tilde{f}}$) be the inverse limit of a continuous surjection f on X. We show that for a continuous surjective map f, if f has the asymptotic average, the average shadowing, the ergodic shadowing property then ${\tilde{f}}$ is topologically transitive.

Design of Porcess Parameters in Axisymmetric Multi-step Deep Drawing by a Finite Element Inverse Method (유한요소 역 해석을 이용한 축대칭 다단계 박판성형에서의 공정변수 설계에 관한 연구)

  • Cho, Cheon-Soo;Lee, Choong-Ho;Huh, Hoon
    • Transactions of Materials Processing
    • /
    • v.6 no.4
    • /
    • pp.300-310
    • /
    • 1997
  • A finite element inverse method is introduced for direct prediction of blank shapes, strain distributions, and reliable intermediate shapes from desired final shapes in axisymmetric multi-step deep drawing processes. This mothod enables the determination of process disign. The approach deals with the Hencky's deformation theory. Hill's second order yield criterion, simplified boundary conditions, and minimization of plastic work with constraints. The algorithm developed is applied to motor case forming, and cylindrical cup drawing with the large limit drawing ratio so that it confirms its validity by demonstrating resonably accurate numerical results of each problem. Numerical examples reveal the reason of difficulties in motor case forming with corresponding limit diagrams.

  • PDF

Development of limit equilibrium method as optimization in slope stability analysis

  • Mendjel, D.;Messast, S.
    • Structural Engineering and Mechanics
    • /
    • v.41 no.3
    • /
    • pp.339-348
    • /
    • 2012
  • The slope stability analysis is usually done using the methods of calculation to rupture. The problem lies in determining the critical failure surface and the corresponding factor of safety (FOS). To evaluate the slope stability by a method of limit equilibrium, there are linear and nonlinear methods. The linear methods are direct methods of calculation of FOS but nonlinear methods require an iterative process. The nonlinear simplified Bishop method's is popular because it can quickly calculate FOS for different slopes. This paper concerns the use of inverse analysis by genetic algorithm (GA) to find out the factor of safety for the slopes using the Bishop simplified method. The analysis is formulated to solve the nonlinear equilibrium equation and find the critical failure surface and the corresponding safety factor. The results obtained by this approach compared with those available in literature illustrate the effectiveness of this inverse method.

Redundant Controls Allocation by a Modified Pseudo Inverse Redistribution Method (수정된 의사역행렬 재분배 기법을 이용한 여유 조종력 할당)

  • Jin, Jae-Hyun;Yoo, Chang-Sun;Ryu, Hyeok;Tahk, Min-Jea
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.32 no.9
    • /
    • pp.65-71
    • /
    • 2004
  • Redundant control surfaces arc adopted to modern aircraft designs because of high performance and fault tolerant control, so efficient redundancy management is necessary to take advantage of redundant control surfaces. This paper focuses on the control allocation scheme as one of redundancy management methods. A modified pseudo inverse redistribution method is proposed. The existing method sets all saturated controls as their limit values when a pseudo inverse is calculated. But the modified scheme sets only one saturated control as its limit value and redistributes remaining controls. It is shown that the proposed scheme is superior to the existing method by several numerical examples.