This paper presents a method to detect multiple cracks based on frequency information. When a structure is subjected to dynamic or static loads, cracks may develop and the modal frequencies of the cracked structure may change. To detect cracks in a structure, we construct a high precision wavelet finite element (EF) model of a certain structure using the B-spline wavelet on the interval (BSWI)....

The article shows the effect of torsional rigidity of beam elements onto spatial work of bridges, floorings and other plate-ribbed systems It is shown that, in determining the torsional rigidity using existing methods it is necessary to have spatial spiral cracks, but torsional rigidity when normal cracks is not researched. A method is described for determining the torsional rigidity of reinfor...

Two decades of operating experience have shown that reducing the corner radius from 12–16 mm to 3 or 4 mm A finite element thermal stress model to compute is beneficial in reducing longitudinal corner cracking.4 In the thermomechanical state of the solidifying shell addition to lessening crack frequency, decreasing the corner during continuous casting of steel in a square billet radius also ten...

conclusions regarding the study limitations, dentinal cracks were observed in all files and distances from the apex. although there was more crack incidence in protaper files, no significant differences were noted regarding the studied systems and sections from the apex. materials and methods in an experimental in vitro trial, 80 maxillary and mandibular first molars were selected and their cro...

To increase the efficiency of electronic devices their structures are getting smaller and the layered constructions are getting more complex. The inspection of these small and thin structures gives new demands on the NDT, especially in lateral and depth resolution. High-end X-ray tomography is one inspection method, which allows detecting cracks or delaminations. However, it is time consuming. ...

The recently developed extended finite element method (XFEM) is applied to compute the steady-state energy release rate of channeling cracks in thin films. The method is demonstrated to be able to model arbitrary singularities by using appropriate enriching functions at selected nodes with a relatively coarse mesh. The dimensionless driving force for channeling cracks is obtained as a function ...

Nondestructive evaluation methods are widely used in quality control processes for critical components in systems such as aircraft engines and nuclear power plants. These same methods are also used in periodic field inspection to assure that the system continues to be reliable while it is in service. This paper describes a detection algorithm to automatically analyze vibrothermography sequence-...

We introduce a continuous damage fiber bundle model and compare its behavior with that of dry fiber bundles. Several interesting constitutive behaviors, such as plasticity, are found in this model depending on the value of the damage parameter and on the form of the disorder distribution. We compare the constitutive behavior of global load transfer models, obtained analytically, with local load...

o bjectives: the objective of this study was to assess the effect of new bonding techniques on enamel surface. materials and methods: sixty upper central incisors were randomly divided into two equal groups. in the first group, metal brackets were bonded using trans- bondxt and, in the second group, the same brackets were bonded with maxcemelite. the shear bond strength (sbs) of both agents to ...