The doctoral thesis deals with fatigue life evaluation of composites structures. The thesis pro-vides complex review of problematic and it is based on recent situation assessment. The main ob-jective of the thesis is to design the methodology of fatigue life evaluation of composites struc-tures. The designed methodology is applied to fatigue life evaluation of sailplane wing and propel-ler blades. One part of the thesis deals with laboratory fatigue tests of composite specimens which are intended for comparison of the effect of manufacturing technology and environment condition.

Approved for public release; distribution is unlimited / Fatigue due to sleep deprivation is a major factor in both mental and physical performance. Failure of Recruits to receive the proper quality and quantity of sleep can be detrimental to a Recruit’s safety and can diminish the amount of information learned during training. During the 1980s, the sleep regimen was decreased to 6 hours of sleep per night. In 2002, a decision was made to give U.S. Navy Recruits an additional two hours of sleep per night. This latest modification was selected to coincide with the acknowledged adolescent/young adult circadian rhythms. The purpose of this study was to determine the impact of the new eight-hour sleep regimen using standardized test scores as a performance measure. One year of data with the eight-hour sleep regimen is compared to two separate years when only six hours of sleep was allowed. There is a significant difference, F(2, 33) = 29.82, p < .0001, between the test scores of Recruits receiving 6-hours of sleep and 8-hours of sleep. On average test scores rose by 11 percent with the additional sleep. The odds of observing such a difference by chance is less than one in ten million. / Lieutenant Commander, United States Navy

Heavy vehicle structures are made from welded carbon steel frames. During operation these frames are subjected to random dynamic loads, which induce fatigue at the welded joints. A Finite Element based process for calculating fatigue life of welded joint under single excitation random loading is proposed in this study. The proposed method com-bines Equivalent Equilibrium Structural Stress (E2S2) method for weld fatigue and PSD based vibration fatigue technique for handling random loads. Fatigue life of a welded T-joint is analysed using the proposed method in frequency domain and validated against a transient dynamic analysis. The main advantage of the proposed method is the analysis run time is reduced almost 12 times compared to transient analysis. Effect of geometric changes on weld fatigue life is studied. It is found the tube thickness increase at lower thickness ranges significantly increases the fatigue life compared to higher thickness ranges. / May 2016

Caring for a new child is a significant, demanding, and time consuming role, often associated with increased stress. Postnatal depression is one possible outcome of increased stress and research has highlighted the importance of detecting depression in new mothers. However fatigue a correlate of depression, has only recently become a focus of research among health professionals. Understanding the nature of fatigue and its management within the postnatal period, the focus of this study, may reduce its impact on women’s lives. This longitudinal study explores changes in intensity, physical, mental and emotional dimensions of fatigue, factors associated with higher levels of fatigue, the impact of fatigue on women’s usual activities, and strategies for managing fatigue. Self-administered structured questionnaires gathered data form 504 women at 1, 6, 12 and 24 weeks after birth. Reliable and valid instruments were used to measure the relationship between the defined factors and the outcome of fatigue at the various time points. State anxiety was a consistently strong predictor of fatigue intensity across time and group. Women sought to manage their fatigue by using self-care practices and asking for help from family and friends. This research highlights two issues for health professionals – care of new mothers must include recognition that higher levels of state anxiety are associated with higher levels of postnatal fatigue: ongoing assessment of fatigue and the strategies used to manage it is essential beyond the early postnatal period / Doctor of Philosophy (PhD)

The maladaptive effects of work-related strain constitute an ongoing and growing problem for many workers in the modern workplace. Contemporary understanding of the physiology of brain arousal processes suggests a consistent balance between brain arousal and recovery over the 24-hour work/rest cycle is crucial for maintaining an adaptative response to work strain. Broadly, intense brain arousal tends to occur at work, whilst its recovery occurs in non-work time, usually at home. This thesis describes the development and validation of a new self-report measure of work-related strain, which incorporates a new and unique measurement of recovery from work strain between successive work periods. This instrument has facilitated several studies of recovery from work-related stress/fatigue, which are reported in the form of papers published, in press or in review with peer-reviewed journals. In particular, it is evident that the type and frequency of non-work time behaviour may be significant in determining the level of recovery from acute work strain. This, in turn, mediates the quality of sleep subsequently achieved, and these combine synergistically to determine overall level of recovery that is achieved between work periods. Consistent with the known physiology of brain arousal and recovery, which is described, non-work time behaviours, which mediate adequate recovery from work strain consistently, may represent the difference between long-term adaptative and maladaptive outcomes of work strain exposure. This suggests an area for work-stress intervention hitherto underestimated in fatigue/stress research. It is argued to be of significance for workers in high stress occupations, since non-work time behaviour is potentially more completely within their discretionary power, than the stress/fatigue levels to which they may be regularly exposed through the inherent nature of their work.

Fibromyalgia Syndrome (FMS) and Chronic Fatigue Immune Dysfunction Syndrome (CFIDS) are primarily womens syndromes. Both syndromes are highly contested within the biomedical and scientific communities and within the general population. Because there is no apparent cause for the syndromes and no available treatment, women living with FMS and/or CFIDS must live with difficult and disabling symptoms. <p>This research also analyzes the metaphors used in the scientific and biomedical literature to describe the same symptoms as listed above. A comparison is drawn between this analysis and that focused on the womens use of metaphors. It is found that although many of the metaphors are the same, they differ in discursive employment. Environmental metaphors, along with metaphors of fracture, harm and productivity are used by the research participants with a very different intent than how the same metaphors are used in the biomedical literature. The women used the metaphors to reveal the ways in which their symptoms are influenced by the social and cultural forces in their everyday lives. The biomedical and scientific use of metaphors reinforced the highly contested view that the symptoms are influenced more by individual psychological and emotional deficiencies than by broader structural forces.

Fibromyalgia Syndrome (FMS) and Chronic Fatigue Immune Dysfunction Syndrome (CFIDS) are primarily womens syndromes. Both syndromes are highly contested within the biomedical and scientific communities and within the general population. Because there is no apparent cause for the syndromes and no available treatment, women living with FMS and/or CFIDS must live with difficult and disabling symptoms. <p>This research also analyzes the metaphors used in the scientific and biomedical literature to describe the same symptoms as listed above. A comparison is drawn between this analysis and that focused on the womens use of metaphors. It is found that although many of the metaphors are the same, they differ in discursive employment. Environmental metaphors, along with metaphors of fracture, harm and productivity are used by the research participants with a very different intent than how the same metaphors are used in the biomedical literature. The women used the metaphors to reveal the ways in which their symptoms are influenced by the social and cultural forces in their everyday lives. The biomedical and scientific use of metaphors reinforced the highly contested view that the symptoms are influenced more by individual psychological and emotional deficiencies than by broader structural forces.

No description available.

No description available.

No description available.