The effect of preexisting subsurface cracks on the strength of lap splices was investigated. Ten full-scale beams with No. 11 (No. 36) bars and lap splice lengths of 33, 79, and 120 in. (838, 2007, and 3048 mm) were tested. The beams had mitigating features that prevented catastrophic failure upon propagation of the preexisting cracks, such as staggered splices and the presence of some reinforc...

Controlled vertical drying deposition method was used to make high-quality single crystal close-packed colloidal films formed of different radii polystyrene latex spheres on glass substrates coming from a low concentration water suspension (0.1% volume fraction). Regardless of the spheres radii the film thickness was about 6.3 microns. However, cracks destroyed the crystalline film structure du...

Consider a three-dimensional homogeneous isotropic elastic solid containing a flat pressurized crack, fi. The problem of finding the resulting stress distribution can be reduced to a hypersingular integral equation over Q for the crack-opening displacement. Here, this equation is transformed into a similar equation over a circular region D, using a conformal mapping between Q and D. This new eq...

In this study, enamel micro-cracks produced around composite restorations were observed on surfaces and vertical sections, using a stereomicroscope and a scanning electron microscope (SEM). The effects of various clinical factors, i.e. the curing system, the marginal form and the polishing period after filling, on the incidence of marginal enamel micro-cracks were examined. Enamel micro-cracks ...

This paper studies the initiation of cohesive cracks in the thermal shock problem through a variational analysis. A two-dimensional semi-infinite slab with an imposed temperature drop on its free surface is considered. Assuming that cracks are periodically distributed and orthogonal to the surface, at short times we show that the optimum is a distribution of infinitely close cohesive cracks. Th...

Effect of Cracks on Elastic Properties of Low Porosity Rocks by Terrence Patrick Todd Submitted to the Department of Earth and Planetary Sciences on May 1, 1973, in partial fulfillment of the requirements for the degree of Doctor of Philosophy Microcracks in terrestrial and lunar rocks significantly alter elastic, thermal, and mechanical properties. The degree to which microcracks alter physica...

ID No: 65 ABSTRACT This research studies the self-healing potential of early cracks in cement-based materials incorporating carbonic anhydrase (CA) bacteria. CA bacteria can accelerate the CO2 hydrated reaction then transfer CO2 to HCO3 which can react with soluble Ca(OH)2 on the surface of specimens. Calcium carbonate deposits because of the reaction of HCO3 with Ca.This research studies the s...

The magnetic flux leakage inspection method is widely used in the detection of pipelines, storage tanks and other steel materials. Especially in corrosion pits detection, it has become a matured technology. As cracks may exist in the steels which may lead to big hazards, its detection becomes very important. Meanwhile, the cracks evaluation by MFL inspection can be determined by many parameters...

The current status o f the problem of small cracks in fatigue is presented. Several classes o f small cracks are distinguished, and their individual characteristics described. Specifically, for cracks small compared with microstructural size scales, for cracks small compared with the ex tent o f local plasticity or for cracks which are either chemically or physically small (e.g. about 1 mm or l...