Topic
Crack closure
About: Crack closure is a research topic. Over the lifetime, 28157 publications have been published within this topic receiving 588158 citations.
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01 Oct 1965
TL;DR: In this paper, a simple method was developed for detecting the shape of the main tensor-cracks in a set of CONCRETE MEMBERS using a simple simulator.
Abstract: A SIMPLE METHOD IS DEVELOPED FOR CALUCLATION OF CRACK WIDTH AND CRACK SPACING IN REINFORCED CONCRETE MEMBERS. THE CRACK WIDTHS DETERMINED BY THIS METHOD WERE COMPARED WITH TEST DATA OBTAINED FROM FLEXURAL AND TENSILE MEMBERS REINFORCED WITH ONE BAR. THE SHAPE OF THE MAIN CRACKS WAS INVESTIGATED BY MEANS OF SHORT TENSION MEMBERS OF A LENGTH EQUAL TO THE SPACING OF THE MAIN TENSION CRACKS. THE INTERNAL CRACK FORMATION WAS DETERMINED DURING LOADING THROUGH INJECTION OF RESIN INTO A FEW TEST SPECIMENS. AFTER THE RESIN HAD HARDENED AND THE TEST MEMBERS WERE CUT OPEN, THE INTERNAL CRACK FORMATION WAS STUDIED. /RRL/A/
139 citations
TL;DR: In this article, the authors investigated the initiation and propagation of fatigue cracks at high and low stresses in aluminium, nickel and copper, and found that crack propagation involving the formation of ripples on the fracture surface occupies, at high stresses, a large portion of the fatigue life and the whole fracture surface area, whereas at lower stresses a considerable part of fracture surface may be covered with ripples if the specimen has been previously annealed, but only a few percent of the total number of cycles are consumed in this type of fracture.
Abstract: The results to date are reported of an investigation into the initiation and propagation of fatigue cracks at high and low stresses in aluminium, nickel and copper. It is shown that crack propagation involving the formation of ripples on the fracture surface occupies, at high stresses, a large portion of the fatigue life and the whole of the fracture surface area, whereas at lower stresses a considerable part of the fracture surface may be covered with ripples if the specimen has been previously annealed, but only a few per cent of the total number of cycles are consumed in this type of fracture. Observations and measurements on the slow initial stages of crack growth at high and low stresses have been made, and it is shown that the variables of metallurgical condition of the specimen, environment and frequency of cycling affect this stage more significantly than propagation involving ripples. In discussion it is suggested that the environment assists the fatigue process by a corrosive action rat...
139 citations
TL;DR: In this paper, the role of longitudinal residual stress on propagation of fatigue cracks was examined in friction stir welds produced in 2024-T351 aluminum alloy and it was found that residual stresses correspond to low crack growth rates outside the weld zone during fatigue loading.
139 citations
TL;DR: In this article, the elasticity problem for an orthotropic strip or a beam with an internal or an edge crack under general loading conditions is considered and numerical results are given for four basic loading conditions, namely, uniform tension, pure bending, three point bending, and concentrated surface shear loading.
Abstract: The elasticity problem for an orthotropic strip or a beam with an internal or an edge crack under general loading conditions is considered. The numerical results are given for four basic loading conditions, namely, uniform tension, pure bending, three point bending, and concentrated surface shear loading. For the strip with an edge crack additional results regarding the crack opening displacements are obtained by using the plastic strip model. A critical quantity which is tabulated is the maximum compressive stress in the plane of the crack. It is shown that this stress may easily exceed the yield limit in compression and hence may severely limit the range of application of the plasticity results.
139 citations
TL;DR: In this article, the authors investigated the influence of a preferred crystallographic orientation on mechanical properties of textured Ti-6Al-4V material and found that high cycle fatigue and fatigue crack growth were performed in vacuum, laboratory air, and a 3.5 pct NaCl solution.
Abstract: Tensile properties, high cycle fatigue strength, and fatigue crack propagation behavior were evaluated on highly textured Ti-6Al-4V material to investigate the influence of a preferred crystallographic orientation on mechanical properties. Thermomechanical treatments were used to develop three different textures: a basal, basal/transverse, and transverse type, all of which exhibited the same homogeneously equiaxed microstructure. The Young’s modulus was found to vary between 107 and 126 GNm-2, and yield strength changed from 1055 to 1170 MNm-2. Ductility was only slightly affected by texture. High cycle fatigue and fatigue crack growth measurements were performed in vacuum, laboratory air, and a 3.5 pct NaCl solution. It is shown that laboratory air can be regarded as a quite corrosive environment. In vacuum the highest fatigue strength values were measured whenever loads were perpendicular to basal planes. However, these conditions had the highest susceptibilities to air and 3.5 pct NaCl solution environments. Nearly no influence of texture on fatigue crack propagation was found in vacuum, but in a corrosive environment crack growth parallel to (0002)-planes was much faster than perpendicular to these planes. To explain the corrosive effect on the fatigue properties of the textured material hydrogen is thought to play a key role.
139 citations