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1

Seismic behavior of a friction-type artificial plastic hinge for the precast beam–column connection

Huang Hua, Li Ming, Zhang Wei, Yuan Yujie

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e201, 2022

EN

This paper proposed a replaceable friction-type artificial plastic hinge (FAPH) to connect the prefabricated concrete members, characterized by direct load transmission and streamlined configuration. The FAPH device replaced the beam-end plastic hinge region in the precast structures, which could protect the concrete joint core area and other concrete components. The experiment of a precast beam–column connection with FAPH and a cast-in-situ beam–column connection was carried out. The experimental results showed that the FAPH connection had better hysteresis performances with higher bearing capacity, energy dissipation, and ductility than the cast-in-situ concrete connection. Moreover, the finite element model was calibrated and employed to perform parametric analyses, including the axial load ratio, the friction factor, the bolt preload, and the initial clearance. The FE analysis results showed that the FAPH connection would have a more attenuation of the friction force under the higher axial load ratio. Besides, the seismic performance of FAPH can be effectively improved with the increase of the friction factor and the bolt preload, and the FAPH connection exhibited a stable performance with various initial clearances. Based on the parametric analysis results, the formulas for the yield and peak bending moment capacity for the FAPH device were proposed.

2

Hardening laws in miltilevel crystal plasticity models and macro effects of complex cyclic loading

Volegov P. S., Trusov P. V., Gribov D. S., Shveykin A. I.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2014

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z. 86 [290], nr 4

639--649

EN

The problem of constructing a physically based hardening laws of mono- and polycrystalline samples in multi-level theories using crystal plasticity is considered, these hardening laws should allow describing the process of the defect structure evolution of the material due to the intensive inelastic deformations. It is also should be applicable to the description of complex and cyclic loading. An approach to the construction of a general and a particular form of hardening law is proposed, which takes into account the interaction of full and split dislocations with each other, forming and destruction of dislocation barriers, annihilation of dislocations during reverse loading and the interaction of intragranular and grain boundary dislocations. Using the obtained hardening law, the known experimental effects of complex and cyclic loading are described.

PL

W artykule przedstawiono problem budowy fizycznie uzasadnionych praw umocnienia próbek mono- i polikrystalicznych w wielowymiarowych teoriach plastyczności krystalicznej. Rozważane prawa umocnienia powinny pozwalać na opis procesu rozwoju struktury uszkodzenia materiału spowodowanej intensywnymi odkształceniami niesprężystymi. Powinny również umożliwiać na opis złożonych i cyklicznych obciążeń. Zaproponowano podejście do budowy ogólnej i szczegółowej postaci prawa umocnienia, które uwzględnia wzajemne oddziaływanie dyslokacji pełnych i wieloczęściowych, kształtowanie i niszczenie barier dyslokacyjnych, anihilację dyslokacji podczas procesu przeciwnego obciążania, oddziaływanie dyslokacji wewnątrz ziarnowych oraz występujących na granicach ziarn. Wykorzystując otrzymane prawa umocnienia, określono znane skutki eksperymentalne złożonego i cyklicznego obciążania.

3

The truss overload analysis under corrosive degradation

Dudda W.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2006

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Vol. 10, No 4

469-475

EN

A contribution to analytical and numerical tools is presented that permits determinist evaluation of structures' behavior under multiparameter and/or cyclic mechanical, thermal and chemical loads. Particular structure elements undergo plastic and corrosive degrada-tion and dissipate energy, which consists of irreversible contributions, like the work of inelastic strains. The construction and its units' lifetime are estimated according to the dissipated energy criterion. Modeling a numerical implementation of degradation effects are discussed, including cyclic plasticity genera by mechanical and thermal loads, stress corrosion, electrochemical corrosion and low-cyclic corrosion

4

Localization and localized fracture phenomena in inealastic solids under cyclic dynamic loadings

Dornowski W., Perzyna P.

Foundations of Civil and Environmental Engineering

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2002

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No. 1

41-86

EN

The main objective of the paper is the investigation of localization and localized fatigue fracture phenomena in thermo-viscoplastic flow processes under cyclic dynamic loadings. Recent experimental observations for cycle fatigue damage mechanics at high temperature and dynamic loadings of metals suggest that the intrinsic microdamage process does very much dependent on the strain rate and the wave shape effects and is mostly developed in the regions where the plastic deformation is localized. The description of kinematics of finite deformations and the stress tensors is presented. The rates of the deformation tensor and the stress tensor are defined based on the Lie derivative. A general constitutive model of elasto-viscoplastic damaged polycrystalline solids is developed within the thermodynamic framework of the rate type covari-ance structure with finite set of the internal state variables. A set of the internal state variables is assumed and interpreted such that the theory developed takes account of the effects as follows: (i) plastic non-normality; (ii) plastic strain induced anisotropy (kinematic hardening); (iii) softening generated by microdamage mechanisms (nucleation, growth and coalescence of microcracks); (iv) thermomechanical coupling (thermal plastic softening and thermal expansion); (v) rate sensitivity; (vi) plastic spin. To describe suitably the time and temperature dependent effects observed experimentally and the accumulation of the plastic deformation and damage during dynamic cyclic loading process the kinetics of microdamage and the kinematic hardening law have been modified. The relaxation time is used as a regularization parameter. Fracture criterion based on the evolution of microdamage is formulated. Utilizing the finite difference method for regularized elasto-viscoplastic model, the numerical investigation of the three-dimensional dynamic adiabatic deformation in a particular body under cyclic loading condition is presented. Particular examples have been considered: (i) Dynamic, adiabatic and isothermal, cyclic loading processes for a thin steel plate with small rectangular hole located in the centre are considered. The accumulation of damage and equivalent plastic deformation on each considered cycle has been obtained. It has been found that this accumulation distinctly depends on the shape of the assumed loading cycle. (ii) A dynamic adiabatic cyclic loading process for a thin steel plate with sharp notch is investigated. The propagation of the macroscopic fatigue damage crack within the material of the plate is investigated. It has been found that the length of the macroscopic fatigue damage crack distinctly depends on the wave shape of the assumed loading cycle. The results obtained are in accord with the experimental observations performed by Sidey and Coffin [65].