This paper addresses the problem of repairing multiple cracked beams subjected to static load using piezoelectric patches. First, is formulated and solved analytically for case two cracks that results in ratio restoring moments produced by employed Since dependent only on crack positions but not their depth, result obtained has been extended cracks. proposition then validated finite element sim...

In the coal mining process, the destabilization of loaded coal mass is a prerequisite for coal and rock dynamic disaster, and surface cracks of the coal and rock mass are important indicators, reflecting the current state of the coal body. The detection of surface cracks in the coal body plays an important role in coal mine safety monitoring. In this paper, a method for detecting the surface cr...

This paper presents a method for predicting initial trajectories of propagation of two separate fatigue cracks, which are developed under two perpendicular cyclic loads with phase difference between them. Calculation of trajectories of these two initial cracks is the first step in prediction of trajectories and rate of propagation of long cracks. This problem is important for analysis of durabi...

Development of macro and micro cracks on plastered walls and floors have been studied at different sites under site investigation whereby building inspections, construction history, engineering properties of soil and building surroundings assessment were conducted. We did revision of structural calculations and laboratory experiment to find out the source of cracks. Micro and macro cracks have ...

During blasting construction in tunnel engineering, an inclined fissure near the blast hole produces “Z” type of over-excavation and subsequently affects overall effect stability tunnel. In this work, dynamic caustics testing was used to study burst propagation mode penetration form explosive cracks at different positions between holes under double-hole conditions. Results showed that existence...

In the bridge inspection, the information of cracks is important to maintain a bridge. Therefore, automatic crack detection is highly desirable for efficiency and objectivity of crack assessment. However, in general, it is very difficult to detect cracks automatically from noisy concrete surfaces. In this paper, we propose a machine vision system for automatic inspection of bridges. The propose...

A defect sensing method based on electrical impedance spectroscopy is proposed to image cracks and reinforcing bars in concrete structures. The method utilizes the frequency-dependent behavior of thin insulating cracks: low-frequency electrical currents are blocked by insulating cracks, whereas high-frequency currents can pass through thin cracks to probe the conducting bars. From various frequ...

To improve the selectivity of closed cracks for objects other than cracks in ultrasonic imaging, we propose an extension of a novel imaging method, namely, subharmonic phased array for crack evaluation (SPACE) as well as another approach using the subtraction of responses at different external loads. By applying external static or dynamic loads to closed cracks, the contact state in the cracks ...

Micro cracks occurring in concrete around tensile rebar is well known latent damage phenomenon. These micro cracks develop, and can be detected after reaching the surface of the concrete. Detection of these cracks before they are fully formed is preferable, but observing the whole crack structure is difficult. Another problem is repairing micro cracks under the concrete surface. The autogenous ...