• Title/Summary/Keyword: contact stiffness

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Influence of interfacial adhesive on the failure mechanisms of truss core sandwich panels under in-plane compression

  • Zarei, Mohammad J.;Hatami, Shahabeddin;Gholami, Mohammad
    • Steel and Composite Structures
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    • v.44 no.4
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    • pp.519-529
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    • 2022

  • Sandwich structures with the superior mechanical properties such as high stiffness and strength-to-weight ratio, good thermal insulation, and high energy absorption capacity are used today in aerospace, automotive, marine, and civil engineering industries. These structures are composed of moderately stiff, thin face sheets that withstand the majority of transverse and in-plane loads, separated by a thick, lightweight core that resists shear forces. In this research, the finite element technique is used to simulate a sandwich panel with a truss core under axial compressive stress using ABAQUS software. A review of past experimental studies shows that the bondline between the core and face sheets plays a vital role in the critical failure load. Therefore, this modeling analyzes the damage initiation modes and debonding between face sheet and core by cohesive surface contact with traction-separation model. According to the results obtained from the modeling, it can be observed that the adhesive stiffness has a significant influence on the critical failure load of the specimens. To achieve the full strength of the structure as a continuum, a lower limit is obtained for the adhesive stiffness. By providing this limit stiffness between the core and the panel face sheets, sudden failure of the structure can be prevented.

  • https://doi.org/10.12989/scs.2022.44.4.519 인용 KSCI

Effective Stiffness of Horizontal Joints in Precast Concrete Large Panel Structures (프리캐스트 콘크리트 대형판구조물의 수평접합부 유효강성)

  • 장극관;이한선;신영식;류진호
    • Proceedings of the Korea Concrete Institute Conference
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    • 1993.10a
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    • pp.278-283
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    • 1993

  • Though stiffnesses of joints in precast concrete (P.C) large structures are known to be generally less than those in monolithic reinforced concrete wall structures, designers have very little information on the quantitative values with regards to these stiffnesses. The aim of this paper is to provide this quantitative information, in particular, on the compressive stiffness of horizontal joints, based on the analytical results derived from several experiments. Also, it is shown that the approach from the contact problem to determine this stiffness gives a value very similar to those obtained above.

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An improved robust hybrid control for uncertain robot manipulators using the stiffness bound of environments (환경의 강성 경계를 이용한 불확실 로봇 시스템의 개선된 견실 하이브리드 제어)

  • 권택준;한명철;하인철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.259-262
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    • 2001

  • An improved robust hybrid control law is proposed. This law used the separated bounding function and the stiffness bound. It satisfied the performance though we don't know precise information of contact environments. It guarantees the practical stability in sense of Lyapunov. Simulation was performed to validate this law using a four-axis SCARA type robot manipulator.

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Establishment of Design Variable of Leg Stiffness Artificial Tendon Actuator ($LeSATA^{TM}$) for Actual Control in Dorsiflexion of Metatarsophalangeal Joint at the Initial Contact while the Bi-pedal Human Walking : (1) Realization of Lagrangian Equation and Impulsive Constraint (2족 보행시 중족지절관절 초기접지기 배측굴곡의 능동적 통제를 위한 Leg Stiffness Artificial Tendon Actuator($LeSATA^{TM}$)의 설계변수 확립 : (1) Lagrangian 방정식 및 Impulsive Constraint 적용법 구현)

  • Kim, Cheol-Woong;Han, Gi-Bong;Eo, Eun-Kyoung
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2010.11a
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    • pp.651-652
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    • 2010

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A hybrid method for dynamic stiffness identification of bearing joint of high speed spindles

  • Zhao, Yongsheng;Zhang, Bingbing;An, Guoping;Liu, Zhifeng;Cai, Ligang
    • Structural Engineering and Mechanics
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    • v.57 no.1
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    • pp.141-159
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    • 2016

  • Bearing joint dynamic parameter identification is crucial in modeling the high speed spindles for machining centers used to predict the stability and natural frequencies of high speed spindles. In this paper, a hybrid method is proposed to identify the dynamic stiffness of bearing joint for the high speed spindles. The hybrid method refers to the analytical approach and experimental method. The support stiffness of spindle shaft can be obtained by adopting receptance coupling substructure analysis method, which consists of series connected bearing and joint stiffness. The bearing stiffness is calculated based on the Hertz contact theory. According to the proposed series stiffness equation, the stiffness of bearing joint can be separated from the composite stiffness. Then, one can obtain the bearing joint stiffness fitting formulas and its variation law under different preload. An experimental set-up with variable preload spindle is developed and the experiment is provided for the validation of presented bearing joint stiffness identification method. The results show that the bearing joint significantly cuts down the support stiffness of the spindles, which can seriously affects the dynamic characteristic of the high speed spindles.

  • https://doi.org/10.12989/sem.2016.57.1.141 인용 KSCI