Main aim of our thesis is fatigue and stress detection from biological signals of a driver. Introduction contains information on published methods of detection and thoroughly informs readers about theoretical background necessary for our thesis. In the practical application we have firstly worked with a database of measured rides and subsequently chose their most relevant sections. Extraction and selection of features followed afterward. Five different classification models for tiredness and stress detection were used in the thesis and prediction was based on actual data. Lastly, the final section compares the best model of our thesis with the already published results.

In spite of its significance in industrial applications, the prediction of the influence of microstructure on the early stages of crack formation and growth in engineering alloys remains underdeveloped. The formation and early growth of fatigue cracks in the high cycle fatigue regime lasts for much of the fatigue life, and it is strongly influenced by microstructural features such as grain size, twins and morphological and crystallographic texture. However, most fatigue models do not predict the influence of the microstructure on early stages of crack formation, or they employ parameters that should be calibrated with experimental data from specimens with microstructures of interest. These post facto strategies are adequate to characterize materials, but they are not fully appropriate to aid in the design of fatigue-resistant engineering alloys. This thesis considers finite element computational models that explicitly render the microstructure of selected FCC metallic systems and introduces a fatigue methodology that estimates transgranular and intergranular fatigue growth for microstructurally small cracks. The driving forces for both failure modes are assessed by means of fatigue indicators, which are used along with life correlations to estimate the fatigue life. Furthermore, cracks with meandering paths are modeled by considering crack growth on a grain-by-grain basis with a damage model embedded analytically to account for stress and strain redistribution as the cracks extend. The methodology is implemented using a crystal plasticity constitutive model calibrated for studying the effect of microstructure on early fatigue life of a powder processed Ni-base RR1000 superalloy at elevated temperature under high cycle fatigue conditions. This alloy is employed for aircraft turbine engine disks, which undergo a thermomechanical production process to produce a controlled bimodal grain size distribution. The prediction of the fatigue life for this complex microstructure presents particular challenges that are discussed and addressed. The conclusions of this work describe the mechanistic of microstructural small crack. In particular, the fatigue crack growth driving force has been characterized as it evolves within grains and crosses to other grains. Furthermore, the computational models serve as a tool to assess the effects of microstructural features on early stages of fatigue crack formation and growth, such as distributions of grain size and twins.

Fatigue and drowsy driving in the state of Utah has been a causal factor in thousands of crashes over the years and poses a serious threat to public safety. Consequently, the purpose of this research was to evaluate the impact of drowsy driving in the state, to identify locations where fatigue and drowsy driving may be contributing factors to current crashes, and to identify methods to help mitigate these crashes. A 3-year drowsy driving crash rate spanning the years 2002 – 2004 was used to determine which segments of Utah highway are most prone to drowsy driving crashes. Drowsy driving corridors were located on Interstates 15, 70, 80, and 84 as well as United States Routes 89 and 91. Furthermore, State Route 36 also had two drowsy driving corridors. In order to recommend appropriate drowsy driving countermeasures for the drowsy driving corridors, a review of the existing countermeasures was conducted. The existing countermeasures included cable median barrier, rumble strips, rest areas, and drowsy driving freeway signage. The freeway signage is used to alert drivers of the adverse effects of drowsy driving and was the basis for a before-after study as well as a public survey of drowsy driving along Interstate 80 west of Salt Lake City. The before-after study of the drowsy driving freeway signage concluded that the freeway signage has played a part in reducing the number of crashes by as much as 63 percent in the eastbound direction and by as much as 22 percent in the westbound direction. As indicated, a public survey was conducted at two rest areas to supplement the findings of the before-after analysis. Using the 405 completed surveys, 14 Chi-Square tests were conducted with five of the test yielding statistically significant results. Finally, recommendations were made for the 41 drowsy driving corridors resulting from the 3-year crash rate analysis. Drowsy driving countermeasures recommended include: additional shoulder and centerline rumble strips, cable median barrier, guardrail replacement, and drowsy driving highway signage. Drowsy driving countermeasures not yet implemented but which should be considered by the Utah Department of Transportation are transverse rumble strips, wider longitudinal pavement markings, in-lane pavement markings indicating “AVOID FATIGUE DRIVING,” minimizing edge drop off, flattening slopes in clear zones, and adding a modified rest area.