Meso-scale modelling of the size effect on the fracture process zone of concrete

The size effect on the fracture process zone in notched and unnotched three point bending tests of concrete beams is analysed by a meso-scale approach. Concrete is modelled at the meso-scale as stiff aggregates embedded in a soft matrix separated by weak interfaces. The mechanical response of the three phases is modelled by a discrete lattice approach. The model parameters were chosen so that the global model response in the form of load-crack mouth opening displacement curves were in agreement with experimental results reported in the literature. The fracture process zone of concrete is determined numerically by evaluating the average of spatial distribution of dissipated energy densities of random meso-scale analyses. The influence of size and boundary conditions on the fracture process zone in concrete is investigated by comparing the results for beams of different sizes and boundary conditions

Meso-scale approach to modelling the fracture process zone of concrete subjected to uniaxial tension

A meso-scale analysis is performed to determine the fracture process zone of concrete subjected to uniaxial tension. The meso-structure of concrete is idealised as stiff aggregates embedded in a soft matrix and separated by weak interfaces. The mechanical response of the matrix, the inclusions and the interface between the matrix and the inclusions is modelled by a discrete lattice approach. The inelastic response of the lattice elements is described by a damage approach, which corresponds to a continuous reduction of the stiffness of the springs. The fracture process in uniaxial tension is approximated by an analysis of a two-dimensional cell with periodic boundary conditions. The spatial distribution of dissipated energy density at the meso-scale of concrete is determined. The size and shape of the deterministic FPZ is obtained as the average of random meso-scale analyses. Additionally, periodicity of the discretisation is prescribed to avoid influences of the boundaries of the periodic cell on fracture patterns. The results of these analyses are then used to calibrate an integral-type nonlocal model

Detraining effect of the post-season on selected aerobic and anaerobic performance variables in national league rugby union players: a focus on positional status

Introduction: The study aimed to assess the effects of 6 weeks post-season detraining in relation to player position on selected anaerobic, aerobic and anthropometric characteristics in sub-elite rugby union players.Methods: 34 English National Division One rugby players (mean age 24.6 ± 3.7 years; stature 184 ± 8 cm) were recruited from one professional club and divided into four groups based on playing positions: Tight five forwards (T5), loose forwards (LF), inside backs (IB), and outside backs (OB). Participants were assessed for body mass, sum of 7 skinfolds, countermovement and squat jump performance, 1 repetition maximum bench press and squat, 40m sprint time, 5m multiple shuttle test, and 20m multi-stage fitness test at baseline and 6 weeks later following the post-seasonal break