The flow of homogeneous fluids through porous media: analogies with other physical problems

Cumulative fatigue damage and life prediction theories: a survey of the state of the art for homogeneous materials

Large strain work hardening and textures

Influence of porosity on compressive and tensile strength of cement mortar

http://mmahdikhani.persiangig.com/Nano/Said_2012_Construction-and-Building-Materials.pdf

Properties of concrete incorporating nano-silica

Compressive and tensile strength of dry Douglas-fir was measured through rapid constant deformation rate tests at temperatures from 25 to 288°C, at initial thermoequilibrium and after 2 h of heating. The tensile strength decreased slowly with increasing temperatures to 175°C. Above 175°C, the tensile strength reduces rapidly. This is attributed to alteration of the cellulosic fraction of wood. The compressive strength decreases more uniformly with temperatures increasing to 288°C due to changes occurring in all three basic wood components with change in temperature. A first-order reaction equation for bond rupture/formation was adopted to describe the response. Including only terms for bond rupture resulted in good correlation to the observed strength response at reaching thermoequilibrium.

Effect of Pyrolytic Temperatures on the Longitudinal Strength of Dry Douglas-Fir

Hot torsion tests have been carried out on aluminum, stainless steel, and silicon steel specimens using a wide range of gage length: radius ratios and bore diameters. For stainless steel, which dynamically recrystallises, a higher strain to maximum stress was found for specimens with a gage length : radius ratio A new effective radius is proposed for calculation of strains, strain rates, and shear stresses from torque-twist data for solid and tubular specimens.

Effect of Specimen Geometry on Hot Torsion Test Results for Solid and Tubular Specimens

The prediction and control of flaws in welds occupy an important role in design against fatigue and fracture failure. However, the present NDT devices can detect only a fraction of the flaws and they do not give the actual size of flaws detected. Using Bayes Theorem, a framework is proposed whereby distributions of flaw size and density are updated from NDT inspection data and the level of repair. The concept is equivalent to a filtering process where the detectability function of the NDT device acts as the filter. The information derived will help planning of NDT inspection programs and consistent code specifications.

Probabilistic Updating of Flaw Information

The porosity and pore size distributions of cement pastes of water/cement ratios of 0.35 and 0.55 were measured by high pressure (50,000 psi) mercury porosimetry. Measurements were made on pastes hydrated from 8 hours to 90 days. The variation of mercury porosity with maturity was found to correlate well with generally held concepts of the hydration of cement paste. Differences in the pore size distributions between pastes of different water/cement ratio lie mainly in the region of large pores.

Capillary Porosity in Hardened Cement Paste

The variation in monotonic and cyclic concentration factors (namely, Kt, Ke, Kσ) due to localized and gross plasticity is presented and discussed for two alloys of contrasting stress-strain behavior, an aluminum alloy 2024 T351 and a mild steel SAE 1015. Thin plates with circular and elliptical holes made of these alloys were subjected to monotonic and cyclic straining in a servo controlled testing machine. Predominant in the monotonic behavior of the concentration factors is the rapid increase in strain concentration factor in notched mild steel plates, attributed to the unrestrained plastic flow (Luders deformation) characteristic of this material. Such behavior is compared to the response of the continuously strain hardening aluminum alloy when subjected to a similar nominal strain history. The dominant feature of the cyclic behavior is the variation in the notch strains as influenced by the overall hardening or softening phenomenon which accompanies cyclic plastic deformation. With the aid of these results, the accuracy of the Neuber rule is checked and restrictions to its application in fatigue life predictions of notched members using smooth specimen data are presented.

VK Sisca

Papers

Effect of Pyrolytic Temperatures on the Longitudinal Strength of Dry Douglas-Fir

Effect of Specimen Geometry on Hot Torsion Test Results for Solid and Tubular Specimens

Probabilistic Updating of Flaw Information

Capillary Porosity in Hardened Cement Paste

Some Studies of the Influence of Localized and Gross Plasticity on the Monotonic and Cyclic Concentration Factors