Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 872 for “"viscoelastic"”.
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Precise energy decay rates for some viscoelastic and thermo-viscoelastic rods
Energy dissipation in systems with linear viscoelastic damping is examined. It is shown that in such viscoelastically damped systems the use of additional dissipation mechanisms (such as boundary velocity feedback or thermal coupling) may not improve the rate of energy decay. The situation where …
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Viscoelastic properties of chitosan
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nutrition and Food Science, 1983.
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A viscous-viscoelastic creep model
… compared with the creep data. In the viscous-viscoelastic creep model the total strain was separated into four strain components: elastic, time-independent plastic, time-dependent-recoverable viscoelastic, and time-dependent-nonrecoverable viscous strain. In this project, only the …
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Implementation of viscoelastic Hopkinson bars
The properties of soft, viscoelastic materials at high strain rates are important in furthering our understanding of their role during blast or impact events. Testing these soft or low impedance materials using metallic bars in a split Hopkinson pressure bar setup, poor signal to noise ratios and …
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Viscoelastic study of cement paste.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1967.
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Finite element analysis of anisotropic viscoelastic composite structures and analytical determination of optimum viscoelastic material properties
Quasi-static linear anisotropic viscoelastic responses of composite structures subjected to mechanical and hygrothermal loads are formulated in terms of finite element algorithms. Laplace and/or Fourier transforms rather than direct time integrations are used in this formulation in order to improve …
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Viscoelastic characterization of polyurea based polymers
Several formulations of sprayed polyurea were considered as an alternative to cast polyurea. Based on results from confined compression experiments on these materials, TRI – 25 was selected as the best alternative material on account of its good flow characteristics at lower stresses. The …
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Computational studies of viscoelastic multiphase flows
… direct numerical simulations (DNS) of viscoelastic two-phase flow problems. The Oldroyd-B constitutive equation is used to model the viscoelastic liquid. The code is used to study transient and steady state shapes of Newtonian and viscoelastic drops in simple shear and buoyancy driven …
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Design tools for linear viscoelastic fluids
… materials – materials that exhibit linear viscoelastic behavior – for design. This work develops the framework necessary to incorporate linear viscoelastic materials into the designer's toolbox. First, we think deeply about ways to describe linear viscoelastic behavior for development of …
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Shear flow instabilities in viscoelastic fluids
… with the theoretical study of the stability of viscoelastic shear flows. It is divided into two parts: part I studies inertialess coextrusion flows at large Weissenberg number where the instabilities are due to discontinuities in the elastic properties, and part II studies the effect of …
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Stresses and displacements in viscoelastic bodies
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1967.
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Experimental characterization of viscoelastic flow instabilities
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1996.
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Viscoelastic characterization of collagen-GAG scaffolds
… or not collagen-GAG scaffolds exhibit linear viscoelastic behavior. Tension tests were performed on dry and hydrated engineered collagen-GAG scaffolds in order to develop a stress-strain curve. Strains that fell in the linear elastic region of these curves were selected and then used in stress …
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Viscoelastic characterization of rubber additive asphalt.
Massachusetts Institute of Technology. Dept. of Civil Engineering. Thesis. 1969. Civ.E.
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A study of biaxial viscoelastic behavior
… to investigate the feasibility of determining a viscoelastic stress-strain law for two (or three) dimensional stress conditions by means of one dimensional tests. The conclusions are based upon comparison of theory and experiment for a creep test of a lead plate, subjected to biaxial tension. The …
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Viscoelastic Models for Ligaments and Tendons
… tissues such as ligaments and tendons are viscoelastic materials. They exhibit a slow continuous increase in strain over time, or creep, when subjected to a constant stress and a slow continuous decrease in stress over time, or stress relaxation, when subjected to a constant strain. …
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Nonlinear viscoelastic characterization of structural adhesives
Measurements of the nonlinear viscoelastic behavior of two adhesives, FM-73 and FM-300, are presented and discussed. Analytical methods to quantify the measurements are given and fitted into a framework of an accelerated testing and analysis procedure. The single integral model used is shown to …
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Nonlinear Viscoelastic Wave Propagation in Brain Tissue
… of three major steps. In the first step, a viscoelastic constitutive model of bovine brain tissue under finite step-and-hold uniaxial compression with 10 1/s ramp rate and 20 s hold time has been developed. The assumption of quasi-linear viscoelasticity (QLV) was validated for strain levels …
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