Bending fatigue of hybrid composite rods
The flexural fatigue behavior of hybrid composite rods comprised of unidirectional carbon and glass fibers was investigated. Damage was evaluated by monitoring stiffness loss as a function of cycles, and bending fatigue failure was defined in terms of strength retention. The acoustic emission technique and microscopic examination were used to characterize damage progression and failure mechanisms. The number of cycles to failure depended on applied stress level, and a two-parameter Weibull analysis was used to incorporate probability of failure to the S–N curve. Damage initiated and propagated as a result of matrix cracking and fiber bundle failures within the GF shell. Bending fatigue damage only initiated when the hybrid was exposed to a deflection in excess of 42% of flexural strength, which does not occur in actual conductor field use. Damage reached a saturation point along the GF/CF interface because of the stress concentration that existed between the two material systems, resulting in asymptotic behavior of the stiffness loss. Because damage did not extend into the CF core, static mechanical properties were retained to ∼85% or more.
Quantification of flexural fatigue life and 3D damage in carbon fibre reinforced polymer laminates
Carbon fibre reinforced polymer (CFRP) laminated composites have become attractive in the application of wind turbine blade structures. The cyclic load in the blades necessitates the investigation on the flexural fatigue behaviour of CFRP laminates. In this study, the flexural fatigue life of the [+45/−45/0]2s CFRP laminates was determined and then analysed statistically. X-ray microtomography was conducted to quantitatively characterise the 3D fatigue damage. It was found that the fatigue life data can be well represented by the two-parameter Weibull distribution; the life can be reliably predicted as a function of applied deflections by the combined Weibull and Sigmodal models. The delamination at the interfaces in the 1st ply group is the major failure mode for the flexural fatigue damage in the CFRP laminate. The calculated delamination area is larger at the interfaces adjacent to the 0 ply. The delamination propagation mechanism is primarily matrix/fibre debonding and secondarily matrix cracking.
Child psychiatry curricula in undergraduate medical education.
OBJECTIVE
To review the literature describing the content and time allocated to undergraduate medical education curricula in child and adolescent psychiatry and make recommendations about child and adolescent psychiatry teaching goals and curricula content.


METHOD
A literature search from 1970 to February 2007 using the key words undergraduate, curriculum, teaching, education, psychiatry, child, adolescent, and medical school, was conducted using PubMed, PsycINFO, and Web of Science.


RESULTS
There is limited agreement about curricula content for undergraduate child and adolescent psychiatry teaching programs in medical schools, with a wide range of objectives identified by different programs. On average, the time allowed for teaching child and adolescent psychiatry is small. There is also great variation in the time allocated by different medical schools. In many countries, the number of child and adolescent psychiatrists with academic appointments is limited, and child and adolescent psychiatry programs are developed and taught by a small number of teaching staff at each medical school.


CONCLUSIONS
Medical schools should reconsider the relatively low priority given to teaching child and adolescent psychiatry to medical students. The child and adolescent psychiatry profession must identify clear learning goals for a longitudinal developmentally appropriate model of child and adolescent psychiatry education commencing at an undergraduate level in medical schools and continuing through residency and fellowships. There is a need to promote national and international standards for teaching in this area and to encourage stronger collaborations between teaching staff across different medical schools.