Search results for "Fracture"

Recommendations for standardization and phenotype definitions in genetic studies of osteoarthritis: the TREAT-OA consortium

2011

Objective: To address the need for standardization of osteoarthritis (OA) phenotypes by examining the effect of heterogeneity among symptomatic (SOA) and radiographic osteoarthritis (ROA) phenotypes. Methods: Descriptions of OA phenotypes of the 28 studies involved in the TREAT-OA consortium were collected. We investigated whether different OA definitions result in different association results by creating various hip OA definitions in one large population based cohort (the Rotterdam Study I (RSI)) and testing those for association with gender, age and body mass index using one-way ANOVA. For ROA, we standardized the hip-, knee- and hand ROA definitions and calculated prevalence's of RO…

Validation of the Western Ontario and McMaster Universities Osteoarthritis Index in Patients Having Undergone Ankle Fracture Surgery

2019

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) is a patient-reported outcome measure (PROM) that is widely used to evaluate the pain, stiffness, and physical function of patients with osteoarthritis of the hip and knee. Although the WOMAC has also been used for patients after foot and ankle surgery, it has not been validated for this purpose. A total of 130 patients with surgically treated ankle fractures completed the WOMAC, Visual Analogue Scale Foot and Ankle (VAS FA), Lower Extremity Functional Scale (LEFS), 15D Health-Related Quality-of-Life Questionnaire (15D), and Visual Analog Scale for General Health (VAS general health) after foot and ankle surgery. The…

Effects of 12-month home-based physiotherapy on duration of living at home and functional capacity among older persons with signs of frailty or with …

2018

Health concerns, such as frailty and osteoporotic fractures decrease functional capacity and increase use of health and social care services in the aging population. The ability to continue living at home is dependent on functional capacity, which can be enhanced by rehabilitation. We study the effects of a 12-month home-based physiotherapy program with 12-month follow-up on duration of living at home, functional capacity, and the use of social and health care services among older persons with signs of frailty, or with a recently operated hip fracture. This is a non-blinded, parallel group, randomized controlled trial performed in South Karelia Social and Health Care District, Finland (popu…

Infrared Thermography assisted evaluation of static and fatigue Mode II fracture toughness in FRP composites

2019

Abstract The work proposes the combined use of a Modified Transverse Crack Tension (MTCT) test coupon and Infrared Thermography, to evaluate the static and fatigue behaviour of Fibre Reinforced Polymer composites under Mode II delamination. Artificial delaminations starters are added to the TCT coupon, whose effects on the Strain Energy Release Rate are discussed. Infrared Thermography and Thermoelastic Stress Analysis are implemented to investigate stresses and delaminations growths on two FRP materials: a pre-preg IM7/8552 carbon fibre-epoxy and a glass-fibre reinforced epoxy laminates. The thermographic, thermoelastic and second harmonic signals have been obtained and used to monitor the…

Thermoelastic Stress Analysis of modified Transverse Cut Tensile composite specimens under pure Mode II fatigue delamination

2018

The present work investigates the behaviour of a Transvers Crack Tensile (TCT) specimen undergoing fatigue loading, by means of a Thermoelastic Stress Analysis (TSA) experimental setup. The TCT is a tensile composite specimen where a number of internal layers are cut through the beam width. The presence of such transverse notch favours the formation of interlaminar Mode II delaminations, starting from the notch tips and propagating between the cut and continuous plies. In this work, a modification is adopted to the classic TCT specimen, where insert films, mimicking artificial delaminations, are laid across the notch tips. This is done with the purpose to favour a pure Mode II and a symmetr…

Characterization of the Altered Zone Around a Fracture in Palmottu Natural Analogue

1996

AbstractA drill core sample penetrating at a natural fracture has been analysed by helium gas techniques and by α-autoradiography. Porosity and diffusivity profiles away from the fracture have been determined and compared with structural profiles. Model calculations are used to determine the effects of sample size on the measured porosities and diffusivities.

Fracture flow due to hydrothermally induced quartz growth

2017

Abstract Mineral precipitations are a common feature and limitation of initially open, permeable rock fractures by forming sealing structures or secondary roughness in open voids. Hence, the objective of this numerical study is the evaluation of hydraulic properties of fractures sealed by hydrothermally induced needle and compact quartz growth. Phase-field models of progressive syntaxial and idiomorphic quartz growth are implemented into a fluid flow simulation solving the Navier–Stokes equation. Flow simulations for both quartz types indicate an obvious correlation between changes in permeability, fracture properties (e.g. aperture, relative roughness and porosity) and crystal growth behav…

Experimental design of the bearing performances of flax fiber reinforced epoxy composites by a failure map

2018

Abstract This paper represents the first effort aimed to the investigation of the pin/hole contact stress and failure mechanisms of epoxy composites reinforced with woven flax fabrics, underwent to tensile bearing tests. In particular, the maximum loads and failure modes are evaluated at varying the laminate geometrical configuration. In order to optimize the use of polymer composites reinforced with flax fibers in structural applications, an experimental failure map, identifying main failure modes of mechanically fastened joints, is obtained as function of hole diameter, distance of the hole from the free edge of the laminate and laminate width. Moreover, a theoretical approach based on th…

Elucidating the Effect of Bimodal Grain Size Distribution on Plasticity and Fracture Behavior of Polycrystalline Materials

2020

The refinement of grains in a polycrystalline material leads to an increase in strength but as a counterpart to a decrease in elongation to fracture. Different routes are proposed in the literature to try to overpass this strength-ductility dilemma, based on the combination of grains with highly contrasted sizes. In the simplest concept, coarse grains are used to provide relaxation locations for the highly stressed fine grains. In this work, a model bimodal polycrystalline system with a single coarse grain embedded in a matrix of fine grains is considered. Numerical full-field micro-mechanical analyses are performed to characterize the impact of this coarse grain on the stress-strain const…

2019

Abstract The fatigue life of thermally sprayed Al2O3- and Cr2O3-based coatings has been studied under low-energy (0.7–5 mJ) impact conditions. A threshold impact energy and amount of repetitions the coatings can endure with said energy before catastrophic failure was obtained. The catastrophic failure was determined to occur when the fracture mode of the coating switched from brittle cone cracking to quasi-plastic radial cracking. The results are examined relative to the microstructural features along with other properties of the coatings - hardness and cavitation resistance. The experiment provided a new approach for a straightforward comparison of the micro-scale impact fatigue life of th…