in classical mechanics, considering hook’s law stress is a linear function of strain. while in strain gradient theory stress is a function of strain and strain differentials. in this paper, novel formulation relating stress and strain and also new boundary conditions are derived based on minimum potential energy principle. in strain gradient theory a length coefficient parameter is defined. thi...

Abstract: The Quasi-static mechanical properties of hybrid fiber (steel fiber and Polyvinyl alcohol (PVA) fiber) reinforced cementitious composites (HFRCC(SP)) were investigated by compressive and tensile experiments. The compressive strength, peak strain, elastic modulus and tensile strength are studied as compared with that of engineered cementitious composite (ECC). Study results indicate th...

a constitutive model based on two–dimensional unstructured galerkin finite volume method (gfvm) is introduced and applied for analyzing nonlinear behavior of cracked concrete structures in equilibrium condition. the developed iterative solver treats concrete as an orthotropic nonlinear material and considers the softening and hardening behavior of concrete under compression and tension by using...

To improve the efficacy of extracorporeal shock wave lithotripsy (ESWL) treatment, it is desirable to identify the physical properties of urinary calculi could offer direct correlation with their fragilities during ESWL and thus could be used to guide treatment procedures for more effective stone fragmentation. Thirty stone specimens removed surgically were compressed by an axial testing system...

Isothermal and constant-strain-rate compression experiments for S280 ultra-high-strength stainless steel were carried out under deformation temperatures of 1000–1150 °C strain rates 0.001–10 s?1 with a Thermecmaster-Z thermal simulator. The flow–stress behavior the alloy was studied hot activation energy calculated. A critical model dynamic recrystallization (DRX) established using work hardeni...

The microstructure and mechanical behavior of commercially pure grade 4 (Gr.4) titanium strips with different deformations were studied by optical microscope (OM), scanning electron microscopy (SEM), transmission (TEM), uniaxial tensile test, hardness test. work-hardening characteristics a Gr.4 strip analyzed true-stress–strain curve. results show that cold deformation can significantly improve...

Rock-like materials are composites that can be regarded as a mixture composed of elastic, plastic, and viscous components. They exhibit viscoelastic-plastic behavior under a high-strain-rate loading according to element model theory. This paper presents an analytical solution for stress wave propagation in viscoelastic-plastic rock-like materials under a high-strain-rate loading and verifies th...

In order to study the variation law of shear frictional characteristics steel pipe jacking and sand interface under different working conditions, stress–strain curve between five particle sizes normal stress slurry lubrication conditions was measured by using a direct device, internal friction angle, coefficient cohesion pipe–soil were calculated regression analysis. The test results show that ...

Fissured rock masses tend to dilate as they are deformed inelastically toward failure. When the rock is fluid saturated and the time scale does not allow drainage, suctions are induced in the pore fluid, and by the effective stress principle the rock is dilatantly hardened over the resistance that it would show to a corresponding increment of drained deformation. This paper considers a compress...

Coal and gas outburst is the result of comprehensive action in situ stress, mechanical properties coal rock. The coupling effect loading adsorption eventually leads to rock failure. Based on principle strain equivalence considering stress loading, an adsorption-loading damage model established which breaks through bottleneck only a single influencing factor. Taking briquette samples with contro...