A nonlinear, finite-element, model is used to examine the biodynamic impact response to helmeted and unhelmeted headforms having human response characteristics. The human response headform is modeled as a spherical brain of nearly incompressible material, a covering of linear elastic dura, a linear elastic spherical skull, and a layer of nonlinear scalp material. The helmet system is modeled as...

in this study, thermo-mechanical nonlinear vibration of a polyethylene (pe) cylindrical shell embedded in an elastic foundation was investigated. the shell is reinforced by armchair carbon nanotubes (cnts) where characteristics of the equivalent composite being determined using mori-tanaka model. the elastic medium is simulated using the spring constant of the winkler-type,  . employing nonline...

in this paper, nonlinear vibration and instability response of an embedded pipe conveying viscose fluid is investigated. the pipe is considered as a timoshenko beam embedded on an elastic foundation which is simulated by spring constant of the winkler-model and the shear constant of the pasternak-model. the external flow force, acting on the beam in the direction of the flexural displacement is...

In the current research, a three-dimensional finite element model was considered to predict the mechanical behavior of Single Wall (SWCNTs) and Multi Wall Carbon Nanotubes (MWCNTs). Assuming the nonlinear elastic behavior of C-C bond in large strains, hyperelastic models were considered. Literature review revealed that the material parameters of the hyperelastic models have been determined from...

  ABSTRACT: A prismatic beam made of a behaviorally nonlinear material situated on nonlinear elastic foundation is analyzed under a moving harmonic load moving with a known velocity. The vibration equation of motion    is derived using Hamilton principle and Euler Lagrange equation. The amplitude of vibration, circular frequency, bending moment, stress and deflection of the beam can be calculat...

We develop a thermodynamic framework for modeling nonlinear ultrasonic damage sensing and prognosis in materials undergoing progressive damage. The framework is based on the internal variable approach and relies on the construction of a pseudo-elastic strain energy function that captures the energetics associated with the damage progression. The pseudo-elastic strain energy function is composed...

The aim of this paper is the variational study of the contact with adhesion between an elastic material and a rigid foundation in the quasistatic process where the deformations are supposed to be small. The behavior of this material is modelled by a nonlinear elastic law and the contact is modelled with Signorini’s conditions and adhesion. The evolution of bonding field is described by a nonlin...

fiber metal laminates (fmls) are new composite materials consisting of thin metal layers and high strength composite layers. arall (aramid aluminum laminate) is a family of the fml that consists of thin aluminum sheets along with kevlar/epoxy composite layers. this material has many advantages such as light weight, excellent corrosion, fatigue and impact resistance. since, arall is a new materi...

any common materials display significant nonlinear rheological properties. Characterizing these roperties can be done with a variety of methods. One such method uses inertio-elastic oscillations, hich occur naturally in rotational rheometry as a consequence of a material’s elasticity and the nertia of the rheometer. These oscillations have primarily been used to characterize linear iscoelastic ...

We report here the first experimental measurements of nonlinear rheological material properties of hagfish slime, a hydrated biopolymer/biofiber network, and develop a microstructural constitutive model to explain the observed nonlinear viscoelastic behavior. The linear elastic modulus of the network is observed to be G′ ≈ 0.02 Pa for timescales 0.1 s ≤ t ≤ 10 s, making it one of the softest el...