Based on Timoshenko-Mindlin shear deformation theory and small deflection hypothesis, the creep buckling for viscoelastic laminated plates and cylindrical shells are analyzed. Laplace Transformation is employed to the governing equation to derive the critic loads in the phase space, and extremum theorems of Laplace Inversion Transformation is then used to acquire the instantaneous critic loads and durable critic loads. It is verified that the results of two types of critic loads, obtained by viscoelastic approach and quasi-elastic approach respectively, are identical.
In this paper, based upon a mechanics model of craze-induced crack and energy absorption rate eriterion, a viscoelastic boundary element method has been developed and applied for calculating the time-dependent opening displacement and envelop stress on the surface of the oraze-induced crack system, and for predicting the creep propagation history of crack in polymer.
Creep-resistant magnesium alloy design, plastic processing of magnesium alloys and rapid solidification processing of magnesium alloys have become the hot topics in magnesium technology.
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Experimental research on the creep behavior and bearing capacity of repeatedly prestressed concrete beam
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Furthermore, a kind of computational formula to calculate creep strain and deformation due to repeated prestressing in terms of time t was derived in this paper and the bearing capacity of this new structure has been tested.
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The measurements were performed with the aid of a dynamic rheology in different regimes including determination of frequency dependences of rheological parameters, creep, and critical strain and stress at which the gelled systems are destroyed.
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Phenomenon of delayed reversible deformation (inverse creep) of solids in surface-active media.
The present paper further applies the Lagrange multiplier method developing in to the flow theory of creep and get a series of generalized variational Principles for small and finite displacements in the theory of creep. Two of these derived variational principles in this paper are the generalized cases of two well-known variational principles of Kachanov. derived from the rate of minimum potential energy and from the rate of minimum complementary. energy. The equivalence of these two gene- rali...
In creep buckling analysis, a ratio stress-strain method is proposed.Making use of a similarity relation among isochronous curves at given temperature, we can condense these curves to a non-dimensional stress-strain curve (i.e. a ratio stress-strain curve) together with a corresponding isochronous modulus-time relation. For the analysis of creep buckling, a ratio stress-strain method is proposed and the critical ratio stress is solved accordingly. Then, one can determine either the critical time...
Mechanical theories of damage are developed from thermodynamics concepts by meansof Kachanov's effective strees.For isotropic three-dimensional damage,an equivalentscalar stress is introduced as a linear combination of mean stress and octahedral shearstress.Then,constitutive equations are written for plastic,creep and fatigue damage phe-nomena.Tests and methods necessary to identify these three models,for each material,aredescribed and damage measurements are taken from damage coupling with elastic be...