Search results for "Fracture"

Paradoxical embolism after a femoral fracture

1998

The foramen ovale is anatomically open in 25 % of individuals, but functionally closed by the higher pressure in the left antrum. Right-to-left shunt and subsequent paradoxical embolism may occur when pressure in the left antrum rises, for example, as a result of pulmonary embolism. In the present case we demonstrate a patient who presented 20 days after osteosynthetic treatment of a femoral fracture with word-finding deficits. Cerebral MRT revealed a fresh ischemic insult. Duplex ultrasound of the legs showed a fresh thrombosis of the superficial femoral vein and scintigraphy of the lungs detected pulmonary embolism. Transesophageal contrast echocardiography trapped a hemodynamically spont…

A DIC-based study of flexural behaviour of roving/mat/roving pultruded composites

2015

Abstract This paper reports a study of the flexural behaviour and resultant failure modes in E-glass/polyester pultruded composites. The digital image correlation (DIC) method is used to estimate the effect of fibre orientation on failure behaviour in thick beams, taking into account the presence of continuous filament mat layer (CFM) in the stacking sequence. In particular, the tests were carried out for specimens with off-axis angle of 0°, 7.5°, 15°, 30°, 45° and 90°. The crack initiation and the failure mechanisms depend on the mutual interaction between the stiffness properties of different areas in the stacking sequence. An influence index (I) was introduced to evaluate the magnitude o…

Digital image correlation analysis of interfacial debonding properties and fracture behavior in concrete

2007

The use of digital image correlation (DIC) as a fracture mechanics tool is described, for two projects currently underway. The goal of the first project is to examine the bond between carbon fiber reinforced polymers (CFRP) and concrete substrates. The second project involves the interfacial transition zone (ITZ) of plain concrete, and the softening and fracture behavior of this region. For both projects, DIC allows for precise measurement of the surface displacements of the deforming materials. The resulting strain data are higher in resolution than is possible with other experimental techniques. For both projects, the DIC results are being used to determine bond constitutive laws, which w…

A family of weakest link models for fiber strength distribution

2007

It is well known that the most widely used distribution function for fiber tensile strength, the two-parameter Weibull distribution, does not always adequately describe the experimentally observed fiber strength scatter and the strength dependence on fiber length. To remedy this discrepancy, modifications of the Weibull distribution have been proposed that, while providing a good empirical fit to the strength data, sometimes lack the theoretical appeal of the weakest link models. We derive a family of weakest link models based on the assumption of a two-stage failure process incorporating explicitly the probabilities of flaw initiation and the fiber fracture due to the largest flaw (i.e. th…

An Intelligent Tool to Predict Fracture in Sheet Metal Forming Operations

2007

One of the main issues in sheet metal forming operations design is the determination of formability limits in order to prevent necking and fracture. In fact, the ability to predict fracture represents a powerful tool to improve the production quality in mechanical industry. Many researchers investigated the problem here addressed, mainly studying forming limit diagrams (FLD) or developing fracture criteria which are able to foresee fracture defects for different processes. In this paper, the author present some early results of a research project focused on the application of artificial intelligence (AI) for ductile fracture prediction in sheet metal forming operations. The main advantage o…

Management of Distal Radius Fractures in the Elderly Patients

2015

Distal radius fractures are one of the most common injuries treated by the orthopedic surgeons representing almost 1/6 of the fractures that are treated in the emergency departments and the 75% of all fractures of the upper limb and are second only to hip fractures in elderly population. The age distribution of this kind of injury is typically bimodal with peaks in the young patients (6-25) and in the elderly patients older than 65. In the first case the mechanism of injury is usually a high energy trauma, such as a car accident, whilst in the second one is usually a low energy trauma like a domestic fall. Various classification systems have been proposed for these fractures. The classic ep…

In Silico Evaluation of Treatment of Periprosthetic Fractures in Elderly Patients After Hip Arthroplasty

2021

The aim of this study was to investigate the soundness of in silico finite element model (FEM) in the assessment of strain in the femur and in the components fixing the periprosthetic fracture in elderly patients after hip arthroplasty. From a group of 55 patients, aged 27–95, treated due to fractures after hip replacement in 2012–2018, 18 patients were separated out, aged over 85, out of whom 7 had type C fractures, according to the Vancouver classification. These seven patients formed the study group. The fractures were stabilized with a locking compression plate system and wire loops or by replacement of the endoprosthesis stem. The FEM was performed by processing radiological images of …

Did the covid-19 pandemic change hip fracture incidence in elderly?

2021

The purpose of this study was to analyze the impact of the national lockdown on femoral neck fractures occurred in the elderly in an Italian city with more than 650 thousand people. We analyzed data related to patients over 65 years-old with femoral neck fractures admitted between March 9th and April 24th, 2020 to five public Hospitals in Palermo and four private Hospitals during lockdown. A total of 152 patients with hip fracture were observed with a significant reduction compared with the same period in 2017-2019. During the Lockdown period a reduction was observed of the mean age from 84.2 ±2.6 years old to 82.5±1.2 with a higher incidence in males, particularly in < 80-year-olds. The…

ELECTROSPUN NANOFIBROUS MATS IN FIBRE REINFORCED EPOXY LAMINATES

Hydrothermal aging of carbon reinforced epoxy laminates with nanofibrous mats as toughening interlayers

2016

Electrospun mats have been applied as toughening interlayers in high performance carbon fiber epoxy composites. While the toughening mechanism exerted by the mat at the interface is the subject of several recent studies, no investigations are reported on the aging behaviour of laminates comprising these nanostructured elements. This work investigates the influence of the combined effect of water and temperature (90 °C) on laminates with Nylon 6,6 electrospun membranes placed either at the middle plane only or at each interlayer. The water-uptake behaviour is modelled by a two-stage diffusion model and compared with the behaviour of the neat resin and of the laminate without mats. Interestin…