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The fatigue behavior of Hilok fastener joints under constant amplitude loading has been investigated experimentally. The effects of load transfer in an unbalanced joint configuration was characterized in terms of a stress severity factor relative to the open-hole configuration. The experimental data indicates that the clamp-up forces dominate the performance of fastener joints with the open-hole fatigue life being the lower bound at the stress levels investigated. The failure modes were observed to transition from a net-section type failure across the minimum section to a fretting induced failure at some distance from the hole. The experimental data has been used to develop stress severity factors to be used as a measure of the fatigue quality of the fastener joints.

This study presents the prediction of the dimensional variation of holes due to sheet metal bending using the hydroforming technique. Sheet metal with pre-drilled holes was evaluated for a bending operation using a hydroforming technique. Sheet metal with a variety of thicknesses, bending radii, and bending angles was evaluated. Variation in the dimensional tolerance due to the bending was attained using the minimum radial separation method. A dataset of dimensional variation in the holes was developed and used for development of the artificial neural network, which was able to predict the dimensional variation of the hole if an unknown pattern of inputs was provided.

Presented here are analyses and statistical summaries of data collected from 11,299 flight operations recorded on 6 BE-1900D aircraft during routine commuter service over a period of three years. Basic flight parameters such as airspeed, altitude, flight duration, etc. are shown in a form that allows easy comparison with the manufacturer's design criteria. Lateral ground loads are presented for ground operations. Primary emphasis is placed on aircraft usage and flight loads. Maneuver and gust loads are presented for different flight phases and for different altitude bands. In addition, derived gust velocities and various coincident flight events are shown and compared with published operational limits.

Flight test experiments were conducted to measure the extent and nature of natural laminar flow on a smoothed test region of a swept-wing business jet wing. Surface hot film aneraometry and sublimating chemicals were used for transition detection. Surface pressure distributions were measured using pressure belts. Engine noise was monitored by a microphone attached to the wing surface to study possible acoustic effects on stability of the laminar boundary layer, Side-slip conditions were flown to simulate changes in effective wing sweep. Flight instrumentation and ground data analysis techniques and a method for measuring intermittency of turbulence are described, Correlation was obtained between the hot film gage signals and chemicals for transition detection. Cross-flow vortices were observed for some flight conditions. Results of spectral and statistical analysis of the hot film signals for various flight test conditions are presented.

Dynamic aircraft seat regulations are identified in the Code of Federal Regulations (CFR), 14 CFR Parts § 23.562 [1] and § 25.562 [2] for crashworthy evaluation of a seat in dynamic environment. The regulations specify full-scale dynamic testing on production seats. The dynamic tests are designed to demonstrate the structural integrity of the seat to withstand an emergency landing event and occupant safety. SAE standard AS 8049 [3] supports detailed information on dynamic seat testing procedure and acceptance criteria. Full-scale dynamic testing in support of certification is expensive and repeated testing due to failure drastically increases the expense. Involvement of impact environment, flexibility in interior configuration and complicated nature of seat engineering design makes this problem quite complex, so that classical hand calculations are practically impossible.

Most composite assemblies and structures generally fail due to weak interlaminar properties and poor performance of their bonded joints that are assembled together with an adhesive layer. Adhesive failure and cohesive failure are among the most commonly observed failure modes in composite bonded joint assemblies. These failure modes occur due to the lack of reinforcement within the adhesive layer in transverse direction. In addition, the laminated composites fail due to the same reason that is the lack of reinforcement through the thickness direction between the laminae. The overall performance of any composite structures and assemblies largely depends on the interlaminar properties and the performance of its bonded joints. Various techniques and processes were developed in recent years to improve mechanical performance of the composite structures and assemblies, one of which includes the use of nanoscale reinforcements in between the laminae and within the adhesive layer.

A supplier satisfaction survey was developed and administered to 129 Aircraft suppliers who are AS9100 registered. The primary objective of the survey was to assess organizational benefits, attributed to the AS9100 standard, and registration process difficulties. Survey results from 49 responses indicated that the primary reason for seeking AS9100 registration was customer requirement, followed by improving production and service. Further analysis indicated that the top three difficulties were evaluating effectiveness of employee training, obtaining and analyzing data on customer feedback and satisfaction, and monitoring and measuring processes. The top three reported benefits, improved quality awareness among employees, an increase in employee training, and improved internal communication, respectively, were all non-financial in nature.