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The yield locus of a cold-rolled transformation-induced plasticity (TRIP780) steel sheet was investigated using a biaxial tensile test on a cruciform specimen. The effect of the key dimensions of the cruciform specimen on the calculation error and stress inhomogeneity was analyzed in detail using an orthogonal test combined with a finite element analysis. Scanning electron metallography (SEM) observations of the TRIP780 steel were performed. The yield curve of the TRIP780 steel was also calculated using the Von Mises, Hill '48, Hill '93, Barlat '89, Gotoh and Hosford yield criteria. The experimental results indicate that none of the selected yield criteria completely agree with the experimental curve. The Hill '48 and Hosford yield criteria have the largest error while the Hill '93 and Gotoh yield criteria have the smallest error.

A series of flight tests were conducted to design and evaluate a Combined Vision System (CVS) that integrates a forward looking infrared video image with synthetic vision on a primary flight display. System features included colorizing the video image to mesh with the synthetic terrain background, decluttering the approach symbology to facilitate the detection of the approach lights and runway markings, creating a semi-transparent IR sky to ensure continuous situational awareness of the surrounding terrain, and annunciating the decision height to facilitate the transition to the actual runway environment. Over 100 approaches were flown during three flight test sessions. For the first flight test session pilots reviewed early CVS proofs of concept on Honeywell's Citation Sovereign.

We present the development of a semiconductor diode laser spectral absorption based gas species sensor for oxygen concentration measurements, intended for life support system monitoring and control applications. Employing a novel self-compensating, noise cancellation detection approach, we experimentally demonstrate better than 1% accuracy, linearity, and stability for monitoring breathing air conditions with 0.2 second response time. We also discuss applications of this approach to CO2 sensing.

We present design considerations of a diaphragm-type spark-plug-integrated fiber-optic combustion pressure sensor employing low-cost sensor and optoelectronic components suitable for large-scale production. Sensor system evaluation data are presented for high-engine-load and high-combustion-temperature conditions, and for knock detection. The fiber-optic sensor output closely resembles that of a heat-sunk, flame-shielded instrumentation-grade piezoelectric reference transducer, and demonstrates a high degree of temperature stability. Better than 4% accuracy is demonstrated over a full-scale pressure range.

A fiber optic in-cylinder combustion pressure sensor system design is presented that exhibits the necessary operation and cost characteristics required for combustion pressure-based engine control applications. The sensor system consists of a small, spark plug-integrated, rugged, and high temperature operable sensor head; a low cost optoelectronic transceiver including LEDs, photodiodes, and simple optical couplers; and a DSP-based signal processing circuitry intended for future ASIC integration. A theoretical approach is developed to predict sensor response and signal-to-noise performance. The agreement between theoretical analysis and experimental results demonstrates that the present low cost system design results in required signal-to-noise performance and provides pressure measurement accuracies better than 5%.