Influence of phase transformations on the mechanical properties of austenitic stainless steels

For more than 30 years the quantitative method of evaluating stability (e.g. Roch, 1966; Fohn, 1987; Jamieson, 1995; Jamieson and Johnston, 1998a) has been focused on calculation of a strength-to-load ratio (or stability index): when the shear stress applied to the weak layer reaches the shear strength, failure is imminent. However, field observations combined with experience and measurements indicate that snow-slab temperatures and slab hardness can have a strong influence on dry-snow slab stability. In this paper, we present a simple static analysis of the stability index, and discuss the importance of slab temperatures and hardness and macroscopic size effects (factors not contained in the stability index) on snow-slab stability. Our conclusion is that the traditional method lacks some elements which are very important in snow-slab stability, particularly when skier triggering is involved.

Skier triggering, snow temperatures and the stability index for dry-slab avalanche initiation

This is Part I of a two-part paper which reviews in depth the literature on the modeling of the propagation of large hydraulic fractures in underground rock formations. Part I presents a general formulation of the problem, its geometry and only the most fundamental and unrestrictive physical assumptions. The two basic two-dimensional models of constant height (rectangular) fractures which formed the core of modeling efforts from 1960 through the late 1970's are discussed in detail followed by a brief review of the effects of fluid diffusion in the fractured medium on crack propagation. The recent field and laboratory observations which have shown that nonrectangular fractures can occur quite often are discussed, as are their impact on the modeling effort, specifically the need for three-dimensional models of crack propagation in layered environments. Part II of the paper deals with the three-dimensional modeling efforts and some fundamental crack and fracture mechanics problems related to the vertical growth of a hydraulic fracture.

A Review of Hydraulic Fracture Modeling—Part I: General Concepts, 2D Models, Motivation for 3D Modeling

Use of nondestructive testing methods in evaluation of thermal damage for ceramics under conditions of nonstationary thermal effects

Creep deformation and rupture properties of unirradiated Zircaloy-4 nuclear fuel cladding tube at temperatures of 727 to 857 K

High-temperature strength of materials

A method of investigating refractory nonmetallic materials in linear thermal loading

1.

We have created a new method of studying the deformation and rupture resistance of commercial glasses and sitals under conditions of biaxial compression (largely eliminating the effect of high contact stresses on the resultant strength and elasticity characteristics) by gluing the ends of the samples into depressions in the metallic bearings with self-hardening compositions; this procedure also enables us to make a valid estimate of the effects of other factors, such as various boundary conditions, the presence of apertures, glued joints, sharp edges and chamfers, mechanical damage, and the etching (pickling) of the lateral surface on the technical strength of brittle materials.




2.

We have found that reliable data regarding the strength of glasses and sitals may be obtained more consistently by using fairly rigid loading devices, preserving the initial contour conditions over the whole range of sample loading, and eliminating possible damage attributable to loss of stability.




3.

We have established that elastic compressive strains in glasses and sitals amounting to at least 2.5% may be measured reliably by means of paper-based strain-gage sensors glued to the fire-polished lateral surface by means of epoxy resin heat-treated at 150°C for 7 h and containing (wt. %): epoxy resin ED-6 74, dibutylphthalate 14.8, and polyethylene polyamine 11.2.




4.

Using the method so developed, we have obtained fresh data regarding the strength of sheet glass subject to linear and plane compression, which, being comparable quantities, may correspond to the first theory of strength or the Mohr criterion.




5.

Under conditions of axial and biaxial compression over the whole range of loads studied (right up to the rupture point), sheet glass constitutes an elastic material with a rectilinear stress-strain diagram.

Method of testing brittle materials such as glasses and sitals under conditions of biaxial compression

1.

Testing based on plane bearings does not give a full representation of the strength of commercial glass under monoaxial compression.




2.

The proposed method of testing compound glass testpieces, based on increasing the load bearing capacity of the ends of smooth rods under compression, provided a means of establishing that the commercial glass adopted by industry has a compressive strength of up to 200–250kgf/mm2 with a small scatter of the data relating to properties.




3.

Mechanical surface damage of commercial glass leads to a considerable reduction of its compressive strength.

G. S. Pisarenko

Papers

High-temperature strength of materials

A method of investigating refractory nonmetallic materials in linear thermal loading

Method of testing brittle materials such as glasses and sitals under conditions of biaxial compression

Method of testing glass in monoaxial compression

Stand for testing glass and ceramic shells under external hydrostatic pressure