Microplane fatigue model MS1 for plain concrete under compression with damage evolution driven by cumulative inelastic shear strain

In this work, an extension of a previously developed continuum based high-cycle fatigue model is enhanced to also capture the low-cycle fatigue regime, where significant plastic deformation of the bulk material takes place. Coupling of the LCFand HCF-models is due to the damage evolution equation. The high-cycle part of the model is based on the concepts of a moving endurance surface in the stress space with an associated evolving isotropic damage variable. Damage evolution in the low-cycle part is determined via plastic deformations and endurance function. For the plastic behaviour a non-linear isotropic and kinematic hardening J2-plasticity model is adopted. Within this unified approach, there is no need for heuristic cycle-counting approaches since the model is formulated by means of evolution equations, i.e. incremental relations, and not changes per cycle. Moreover, the model is inherently multiaxial and treats the uniaxial and multiaxial stress histories in the same manner. Calibration of the model parameters is discussed and results from some test cases are shown.

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Pressure-sensitive bond fatigue model with damage evolution driven by cumulative slip: Thermodynamic formulation and applications to steel- and FRP-concrete bond

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2018.04.020 ◽

2018 ◽

Vol 113 ◽

pp. 277-289 ◽

Cited By ~ 5

Author(s):

Abedulgader Baktheer ◽

Rostislav Chudoba

Keyword(s):

Damage Evolution ◽

Pressure Sensitive ◽

Fatigue Model

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Quantitative damage evolution in dynamic incipiently failed Ti-6Al -4V

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:20009121 ◽

2000 ◽

Vol 10 (PR9) ◽

pp. Pr9-729-Pr9-734

Author(s):

D. A.S. Macdougall ◽

W. R. Thissell

Keyword(s):

Damage Evolution

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Analysis of magneto rheological elastomers for energy harvesting systems

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209350 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 439-446

Author(s):

Gildas Diguet ◽

Gael Sebald ◽

Masami Nakano ◽

Mickaël Lallart ◽

Jean-Yves Cavaillé

Keyword(s):

Magnetic Field ◽

Energy Harvesting ◽

Shear Strain ◽

Magnetic Induction ◽

Magnetic Particles ◽

Homogeneous Magnetic Field ◽

Electrical Signal ◽

Harvesting Systems ◽

Dc Bias ◽

Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

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On the nominal transverse shear strain to characterize the severity of creasing

TAPPI Journal ◽

10.32964/tj17.04.231 ◽

2018 ◽

Vol 17 (04) ◽

pp. 231-240

Author(s):

Douglas Coffin ◽

Joel Panek

Keyword(s):

Shear Strain ◽

Transverse Shear ◽

Elastic Limit ◽

Experimental Results ◽

Transverse Shear Strain ◽

Maximum Strain ◽

Machine Direction ◽

Engineering Approach ◽

Wide Range ◽

Analytic Expression

A transverse shear strain was utilized to characterize the severity of creasing for a wide range of tooling configurations. An analytic expression of transverse shear strain, which accounts for tooling geometry, correlated well with relative crease strength and springback as determined from 90° fold tests. The experimental results show a minimum strain (elastic limit) that needs to be exceeded for the relative crease strength to be reduced. The theory predicts a maximum achievable transverse shear strain, which is further limited if the tooling clearance is negative. The elastic limit and maximum strain thus describe the range of interest for effective creasing. In this range, cross direction (CD)-creased samples were more sensitive to creasing than machine direction (MD)-creased samples, but the differences were reduced as the shear strain approached the maximum. The presented development provides the foundation for a quantitative engineering approach to creasing and folding operations.

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