BACKGROUND Differential-type and integral-type formulations are two common approaches in modeling viscoelastic materials. A differential-type theory is often derived from a Helmholtz free energy function and is usually more suitable for the prediction of strain-rate dependent mechanical behavior during rapid loading, while an integral-type theory usually captures stress relaxation more efficien...

introduction: nano-indentation has recently been employed as a powerful tool for determining the mechanical properties of biological tissues on nano and micro scales. a majority of soft biological tissues such as ligaments and tendons exhibit viscoelastic or time-dependent behaviors. the constitutive characterization of soft tissues is among very important subjects in clinical medicine and espe...

background: in survival studies when the event times are dependent, performing of the analysis by using of methods based on independent assumption, leads to biased. in this paper, using copula function and considering the dependence structure between the event times, a parametric joint distribution has made fitting to the events, and the effective factors on each of these events would be determ...

in this paper, the conjugate gradient method coupled with adjoint problem is used in order to solve the inverse heat conduction problem and estimation of the time- dependent heat flux using the temperature distribution at a point in a three layer system with none homogeneous boundary conditions. also, the effect of noisy data on final solution is studied. for solving this problem the general co...

Abstract Time-dependent rock deformation is considered to precede dynamic failure in many rock-engineering projects and natural geohazards. In order understand long-term performance of brittle rocks, we gather mechanical load, strain, acoustic emission (AE) digital image correlation (DIC) data describe the evolution damage cracking response tensile loading during multi-stage relaxation experime...

in this paper, the propagation of the waves in the laminated composite plates which is subjected to low velocity impact is investigated using the finite element method. a rigid metallic projectile with spherical nose is considered and the impact of this projectile with laminated composite is studied in this study. considering a finite element model the governing equations of the problem is disc...

Modeling buildings response to blast and subsequent progressive collapse interested more and more researchers during the past two decades. Due to the threat from extreme loading, efforts have been made to develop methods of structural analysis and design. In this paper, progressive collapse capacity of steel moment frames was first investigated using alternate load path method, then a nonlinear...