Search results for "Fracture"
showing 10 items of 873 documents
Mode I fracture toughness behaviour of epoxy resincarbon fiber composites cured by ionising radiation
2012
In this work Mode I fracture toughness behavior of Electron Beam cured unidirectional CFRP laminates is investigated by means of standardized Double Cantilever Beam (DCB) tests. A matrix system, comprising a DGEBA epoxy monomer and a typical initiator of cationic polymerization, was used and panel samples assembled by hand lay-up. Curing was achieved by 20 to 40 minutes irradiation on a pulsed 10 MeV Electron Beam accelerator. One batch of resin was also mixed with 10 phr of a PES thermoplastic monomer in order to enhance the matrix toughness. The influence of fibre-matrix adhesion, matrix toughening and matrix crosslinking density on the mode I delamination behavior have been investigated …
Experimental evaluation of through-the-thickness stress distribution in transverse crack tension test samples
2015
Transverse Crack Tension (TCT) samples represent an alternative to End Notched Flexure configurations for the characterization of pure mode II fracture toughness of Fibre Reinforced Polymer composites. TCT is supposed to reproduce a pure Mode II failure mechanism while avoiding the frictional energy dissipation between the flanks of a starter crack. The TCT geometry is that of a unidirectional tensile sample where a number of embedded plies, centered on the middle plane, are cut in the transverse fibres direction. The tensile loading should then activate four symmetric fronts of mode II delamination from the transverse cut tips. The present work describes the implementation of two full fiel…
Failure modelling of friction stir welded joints in tensile tests
2009
BPCO E OSTEOPOROSI
2013
COPD and osteoporosis are frequently associated because they have common risk factors, including age, smoking habits and reduced physical activity. COPD is also characterized by systemic inflammation, malnutrition (up to cachexia), hypovitaminosis D, and the use of local and systemic corticosteroids, all of which could cause deterioration in bone quality with a consequent increase in fragility fractures. These fractures may further impair mobility and increase disability and mortality. The vertebral and rib fractures can directly further affect lung function and promote exacerbations. As a result, the assessment of fracture risk in patients with COPD is of vital importance from the earliest…
FRAGILITY FRACTURES IN OLDER PERSONS WITH ALTERED THYROID FUNCTION
2016
Gli ormoni tiroidei sono peptidi che svolgono molteplici e complesse funzioni nell’organismo umano. Lo sche-letro è uno dei tessuti bersaglio degli ormoni tiroidei, ed una loro carenza o un loro eccesso ha importanti conseguenze sul tessuto osseo soprattutto nel periodo dello sviluppo e durante l’invecchiamento. I disturbi a carico della tiroide si osservano con maggior frequenza nei soggetti in età avanzata rispetto ai giovani. La tire-otossicosi è una causa nota di osteoporosi secondaria. L’ipertiroidismo conclamato e l’ipertiroidismo iatrogeno dovuto ad un eccesso nel dosaggio della terapia sostitutiva con ormoni tiroidei sono possibili cause di fratture ossee da fragilità. L’ipertiroidi…
IL PAZIENTE ANZIANO CON FRATTURA DI FEMORE: VALUTAZIONE E SUPPORTO NUTRIZIONALE
2013
Osteoporosis in the elderly population is a major health problem worldwide, because it is associated with fragility fractures with consequent financial burden for health systems. Europe and North America are the regions where half of all hip fractures among elderly people occurred today, with Scandinavian countries reporting the highest incidence worldwide. Undernutrition, particularly protein malnutrition, is frequent in elderly with osteoporotic hip fracture, although, the role of dietary protein intake in osteoporosis remains controversial. Poor nutritional status is associated with higher comorbidity indices, mortality and readmissions in patients with femoral fracture. Another crucial …
Bisphosphonate-associated femoral fracture: implication for management
2008
Studies carried out on individuals being treated long term with bisphosphonates have provoked considerable interest and perplexity about the effect that these drugs have on bone turnover in the long run. In fact the experiences reported by numerous researchers tend to highlight how treatment with high doses of bisphosphonates over many years, of individuals with osteoporosis complicated by or secondary to neoplastic pathologies, causes a suppression of bone turnover that over time predisposes the bone to the accumulation of micro damage that can then result in complicated fractures, as in the case described here.
Supracondylar femoral fracture with an incidental enchondroma of the tibial plateau
2019
The enchondroma is a benign tumor of the endosteal cartilage and it is common in young-adult patients. These tumors are usually diagnosed when a pathologic fracture occurs at the site of the lesion or when they are accidentally discovered during investigations performed for other reasons. This report describes the case of a patient with an enchondroma of the external tibial plateau. Diagnosis was made treating an ipsilateral supracondylar femoral fracture caused by a traffic accident
Evolution and healing of fragility fractures of the proximal femur
2014
After a traumatic fracture a physiological process begins to heal the fracture. The steps of the process are inflammation, granulation, formation of fibrous callus and finally bone. There are many factors that may influence the healing of the fracture: adequate blood supply, good contact between bone fragments, good stability of the fracture, general health, age, smoking, related pathology, use of drugs, etc. In elderly patients the variations in bone structure and healing processes have a negative influence on fracture healing. Fragility fractures require careful placement of the implants to reduce the risk of failure of osteosynthesis. Appropriate surgical devices and facilitation factors…