The overall objective of the DARPA Structural Integrity Prognosis System (SIPS) program is to develop technologies to advance material damage state condition assessment with limited or no dedicated maintenance action. As a part of the sensors thrust area, an in situ ultrasonic sensing method was developed and demonstrated to detect cracks initiating from fastener holes and provide an estimate o...

The evaluation of stress intensity factors (SIFs) for cracks in mechanically fastened joints is one of the central issues in a damage tolerance analysis. Accurate stress intensity solutions may be difficult to determine due to geometric complexity along with variations in fastener load transfer and fastener interference and material thickness because of corrosion. Detailed finite element models...

This paper presents an investigation of the fatigue crack growth (FCG) behavior at fastener holes in a high strength steel. 30CrMnSiNi2A, before and after a cold-expansion process. The fatigue life of coldworked specimens was signitkantly increased compared to non-wldworked ones and increased the !O\ver applied stress level. From a study' nf the residual stress distribution near the edgc of the...

.................................................................................................................... 2 INTRODUCTION ............................................................................................................. 4 STATEMENT OF THE PROBLEM .................................................................................. 5 SIGNIFICANCE OF THE PROBLEM ..................

Railway inspection is an important task in railway maintenance to ensure safety. The fastener is a major part of the railway which fastens the tracks to the ground. The current article presents an efficient method to detect fasteners on the basis of image processing and pattern recognition techniques, which can be used to detect the absence of fasteners on the corresponding track in high-speed(...

In this paper, fatigue strength of the engine damper cap screw bolt is determined. Engine damper cap screw is critical fastener. Critical fastener is a term used to describe a cap screw that, upon failure, causes immediate engine shutdown or possible harm to person. So, determination of fatigue strength is important. S-N method is used for cap screw fatigue strength determination by testing num...

In this paper, the problems of composite-patch repair of (i) center and edge-cracked panels loaded in the far-field; and (il) cracks emanating from pin-loaded fastener holes, are examined in thorough detail. The effects of various non-dimensional design parameters on the reduction in the stress-mtensity factors near the crack-tip are determined, and are presented in the form of design charts. B...

An integrated approach was developed to assess exposure and health-risk from polycyclic aromatic hydrocarbons (PAHs) contained in oil mists in a fastener manufacturing industry. One previously developed model and one new model were adopted for predicting oil mist exposure concentrations emitted from metal work fluid (MWF) and PAHs contained in MWF by using the fastener production rate (Pr) and ...