Viscoelasticity — Basic Theory and Applications to Concrete Structures

Creus, Guillermo J.

doi:10.1007/978-3-642-82686-3

Cited by 38 publications

(24 citation statements)

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“…For the current study, however, this procedure was simplified so that a series of only two Maxwell elements were used. The stress relaxation behavior of the two‐element model is described by where σ is the stress at time t , σ 0 is the stress at time t =0, C 1 and C 2 are constants, and τ 1 , τ 2 are relaxation times 17 . The data were fitted to the above equation using a standard curve‐fitting procedure in LABVIEW 7.0.…”

Section: Methodsmentioning

confidence: 99%

Effect of Relative Humidity on the Viscoelastic and Mechanical Properties of Spray‐Dried Powder Compacts

Uppalapati

Green

2006

Journal of the American Ceramic Society

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Spray‐dried powder compacts exhibit viscoelastic properties such as stress relaxation, creep, and delayed elastic strain. This behavior is attributed to the organic binder, which forms bridges between the particles in spray‐dried granules, thereby affecting their deformation characteristics. The viscosity and distribution of the binder within the powder compact can affect its mechanical and viscoelastic properties. In this study, the powder was conditioned at different ambient relative humidity (RH) levels, to vary the binder viscosity. Load deformation, stress relaxation, fracture strength, and fracture toughness behavior of ferrite powder compacts were studied as a function of ambient RH both before and after compaction. The loading rate was found to significantly affect the time‐dependent response, and the relaxation times decreased at high humidity levels during compaction. It is proposed that increasing the humidity level during compaction increases the number of particle–particle contacts. This simple mechanism of binder redistribution led to slower relaxation times, increases in fracture strength, and elastic modulus of the green bodies, without significantly altering the fracture toughness when powders were compacted at high humidity to a given density.

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Section: Methodsmentioning

confidence: 99%

Effect of Relative Humidity on the Viscoelastic and Mechanical Properties of Spray‐Dried Powder Compacts

Uppalapati

Green

2006

Journal of the American Ceramic Society

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“…Note that σ(t) = E e (t), and σ(t) = η˙ v (t) where η > 0 is the Newtonian viscosity and E is the Young's modulus. One can derive the constitutive equation of this model as follows (e.g., [7,10]):…”

Section: Linear Viscoelastic Modelmentioning

confidence: 99%

Validation Framework of the Finite Element Modeling of Liver Tissue

Shi

Fahmi

Farag

2005

Lecture Notes in Computer Science

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Abstract. In this work, we aim at validating some soft tissue deformation models using high resolution Micro Computed Tomography (Micro-CT) and medium resolution Cone-Beam CT (CBCT) images. These imaging techniques play a key role in detecting the tissue deformation details in the contact region between the tissue and the surgical tool (probe) even for small force loads, and provide good capabilities for creating accurate 3D models of tissues. Surgical simulations rely on accurate representation of the mechanical response of soft tissues subjected to surgical manipulations. Several finite element (F.E.) models have been suggested to characterize soft tissues. However, validating these models for specific tissues still remains a challenge. For our validation, ex vivo lamb liver is chosen to validate the linear elastic model (LEM), the linear viscoelastic model (LVEM), and the neo-Hooke hyperelastic model (NHM). We found that the LEM is more applicable to lamb liver than the LVEM for small force loads (< 40g) and that the NHM is closer to reality than the LVEM for this same range of force loads.

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“…Rheological models are useful to give an intuitive interpretation to mathematical relationships [8,29]. Models with time-dependent (or age-dependent) parameters can be used to represent the behaviour of ageing materials, as concrete or polymers.…”

Section: Rheological Modelsmentioning

confidence: 99%