The finite element alternating method is an attractive and efficient method for calculating the stress intensity factor of cracks emanating from fastener holes such as the problem of multiple site damage (MSD) at the fuselage skin of aging aircraft. While the alternating method has been used to solve various engineering problems in assessing the structural integrity of aging aircraft, this meth...

The statics and dynamics of pneumatic power screwdriver operation were investigated in the context of predicting forces acting against the human operator. A static force model is described in the paper, based on tool geometry, mass, orientation in space, feed force, torque build up, and stall torque. Three common power hand tool shapes are considered, including pistol grip, right angle, and in-...

BACKGROUND Conventional screws used for fracture fixation in orthopedic surgery continue to rely on the historic buttress thread design. While buttress screws generally provide solid resistance against unidirectional axial loading forces, their design suffers from several limitations, as the buttress thread does not adequately resist multiaxial forces. Furthermore, the buttress screw is prone t...

This paper presents an overview of Laser Shock Processing and then discusses how the process can be extended to treat fastener holes on aging aircraft. The process is used to treat localized fatigue-critical areas by developing deep residual compressive stresses to inhibit the initiation and propagation of fatigue cracks. This feature can be applied to fastener holes in aircraft structures to d...

ANALYSIS OF A DESIGN FOR ITS QUALITY MANUFACTURABILITY IN TERMS OF MISALIGNMENTS AND FASTENER RELATED PROBLEMS.

This study investigated the relationship between pneumatic nutrunner handle reactions, workstation characteristics, and prevalence of upper limb injuries in an automobile assembly plant. Tool properties (geometry, inertial properties, and motor characteristics), fastener properties, orientation relative to the fastener, and the position of the tool operator (horizontal and vertical distances) w...

ABSTRACT. A full scale wing panel fatigue test was undertaken in 2007 as a part of the DARPA Structural Integrity Prognosis System (SIPS) program. Both local and global ultrasonic sensors were installed on the wing panel and data were recorded periodically over a period of about seven weeks. The local ultrasonic sensors interrogated a small number of selected fastener holes, and the global ultr...

Features are investigated in eddy current data that are sensitive to corrosion and fatigue cracks in airframe structures while invariant to other NDE noise factors. To investigate subsurface corrosion characterization at the faying surface, a series of eddy current studies were performed using an analytical model for varying total subsurface thickness loss and percentage of the thickness loss o...

An in situ ultrasonic angle beam method has been developed to detect and size fatigue cracks emanating from fastener holes. The method employs transducers mounted in a pitch-catch configuration on each side of the hole, and the modulation of received signals with load is used to detect and size small fatigue cracks. The focus of this paper is the monitoring of a series of critical fastener hole...

BACKGROUND This study compares the influence of two different annuloplasty attachment suture applications, namely the use of an automated fastener versus manually tied knots using a traditional knot pusher, on total operation time, on cardiopulmonary-bypass time and on cross-clamp time, and on short-term outcome. METHODS Sixty patients underwent isolated minimally invasive mitral valve repair...