An implicit material point-to-rigid body contact approach for large deformation soil-structure interaction

Modelling the interaction between rigid and deformable bodies holds significant relevance in geotechnical engineering, particularly in scenarios involving stiff engineering objects interacting with highly deformable material such as soil. These processes are challenging due to the combined nonlinear mechanisms including large deformation, elasto-plasticity, and contact with friction. For highly deformable material, the Material Point Method is a natural choice over the Finite Element Method due to its ability to handle large deformations without remeshing by carrying material information at points. This paper uses the Implicit General Interpolation Material Point Method (GIMPM) to demonstrate a new approach for modelling this type of interaction, and exploits the GIMPM’s inherent definition of the boundary of a deformable domain to formulate a consistent contact formulation, negating the need for boundary reconstruction. The formulation is demonstrated through validations and comparisons to alternative methods for simulating contact. The combination of the contact formulation with an implicit framework is shown to be an efficient method for modelling geotechnical problems. The proposed method exhibits optimal convergence for contact problems, accurately captures stick-slip Coulomb friction, and ensures consistent stress fields at the contact surface of a rigid body

An implicit material point-to-rigid body contact approach for large deformation soil-structure interaction

Modelling the interaction between rigid and deformable bodies holds significant relevance in geotechnical engineering, particularly in scenarios involving stiff engineering objects interacting with highly deformable material such as soil. These processes are challenging due to the combined nonlinear mechanisms including large deformation, elasto-plasticity, and contact with friction. For highly deformable material, the Material Point Method is a natural choice over the Finite Element Method due to its ability to handle large deformations without remeshing by carrying material information at points. This paper uses the Implicit General Interpolation Material Point Method (GIMPM) to demonstrate a new approach for modelling this type of interaction, and exploits the GIMPM's inherent definition of the boundary of a deformable domain to formulate a consistent contact formulation, negating the need for boundary reconstruction. The formulation is demonstrated through validations and comparisons to alternative methods for simulating contact. The combination of the contact formulation with an implicit framework is shown to be an efficient method for modelling geotechnical problems. The proposed method exhibits optimal convergence for contact problems, accurately captures stick-slip Coulomb friction, and ensures consistent stress fields at the contact surface of a rigid body

Cardiorespiratory fitness is associated with physical literacy in a large sample of Canadian children aged 8 to 12 years

Background The associations between cardiorespiratory fitness (CRF) and physical literacy in children are largely unknown. The aim of this study was to assess the relationships between CRF, measured using the 20-m shuttle run test (20mSRT), and components of physical literacy among Canadian children aged 8–12 years. Methods A total of 9393 (49.9% girls) children, with a mean (SD) age of 10.1 (±1.2) years, from a cross-sectional surveillance study were included for this analysis. The SRT was evaluated using a standardized 15 m or 20 m protocol. All 15 m SRTs were converted to 20mSRT values using a standardized formula. The four domains of physical literacy (Physical Competence, Daily Behaviour, Motivation and Confidence, and Knowledge and Understanding) were measured using the Canadian Assessment of Physical Literacy. Tertiles were identified for 20mSRT laps, representing low, medium, and high CRF for each age and gender group. Cohen’s d was used to calculate the effect size between the low and high CRF groups. Results CRF was strongly and favourably associated with all components of physical literacy among school-aged Canadian children. The effect size between low and high CRF tertile groups was large for the Physical Competence domain (Cohen’s d range: 1.11–1.94) across age and gender groups, followed by moderate to large effect sizes for Motivation and Confidence (Cohen’s d range: 0.54–1.18), small to moderate effect sizes for Daily Behaviour (Cohen’s d range: 0.25–0.81), and marginal to moderate effect sizes for Knowledge and Understanding (Cohen’s d range: 0.08–0.70). Conclusions This study identified strong favourable associations between CRF and physical literacy and its constituent components in children aged 8–12 years. Future research should investigate the sensitivity and specificity of the 20mSRT in screening those with low physical literacy levels

A role for gut-associated lymphoid tissue in shaping the human B cell repertoire

PMCID: PMC3754866Rockefeller University Press grants the public the non-exclusive right to copy, distribute, or display this Work under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ and http://creativecommons.org/licenses/by-nc-sa/3.0/legalcode