An extended finite element method with smooth nodal stress

The enrichment formulation of double-interpolation finite element method (DFEM) is developed in this paper. DFEM is first proposed by Zheng \emph{et al} (2011) and it requires two stages of interpolation to construct the trial function. The first stage of interpolation is the same as the standard finite element interpolation. Then the interpolation is reproduced by an additional procedure using the nodal values and nodal gradients which are derived from the first stage as interpolants. The re-constructed trial functions are now able to produce continuous nodal gradients, smooth nodal stress without post-processing and higher order basis without increasing the total degrees of freedom. Several benchmark numerical examples are performed to investigate accuracy and efficiency of DFEM and enriched DFEM. When compared with standard FEM, super-convergence rate and better accuracy are obtained by DFEM. For the numerical simulation of crack propagation, better accuracy is obtained in the evaluation of displacement norm, energy norm and the stress intensity factor

Disruption and Dissonance: Exploring Constructive Tensions Within Research in Medical Education

The academic medicine community has experienced an unprecedented level of disruption in recent years. In this context, the authors consider how the disruptions have impacted the state of research in medical education (RIME). The articles in this year\u27s RIME supplement reflect several constructive tensions that provide insight on future for the field. In this commentary, the authors discuss themes and propose a framework for the future. Recommendations include: normalizing help seeking during times of disruption and uncertainty, contextualizing the application of complex approaches to assessment, advancing and problematizing innovation, and recognizing the deeply embedded and systemic nature of inequities

The current utility and future use of the medical student performance record: A survey of perceptions across Canada

Introduction: The MSPR is a Canada wide tool that provides aggregate information on MD students’ performance during training and used widely as part of PG admissions. This survey study elicits the perceptions of PG admissions stakeholders on the current use and future utility of the MSPR in Canada. Methods: PG admissions stakeholders across the faculties of medicine were convenience sampled for a 15-question online survey in the fall of 2018. Participants were asked how and when the MSPR is incorporated into the admissions process and perceptions and recommendations for improvement Data are summarized descriptively and thematically. Results: Responses came from 164 participants across the 17 faculties of medicine. The MSPR was widely used (92%), most commonly in the file review process (52%) for professionalism issues. The majority of responses indicated that MSPRs were not fair for all MD students (60%) and required revision (74%) with greater emphasis required on transparency, professionalism, and narrative comments. Discussion: The results indicate that though MSPRs are widely used in PG admissions their perceived value is limited to a few specific sources of information and to specific parts of the admissions process. There are significant concerns from PG stakeholders on the utility of MSPRs and future changes should align with the needs of these stakeholders while balancing the concerns of students and undergraduate programs

Simulation of self-compacting steel fibre reinforced concrete using an enhanced SPH methodology

Accurate prediction of self-compacting fibre reinforced concrete (SCFRC) flow, passing and filling behaviour is not a trivial task, particularly in the presence of heavy reinforcement, complex formwork shapes and large size of aggregates. In this regard, complex formwork shapes and large size of aggregate can play an important role in fibre orientation and distribution during the flow of fibre reinforced self-compacting concrete and can thus significantly influence mechanical behaviour of the hardened material. Due to the nature of selfcompacting concrete mix and widely varying properties of its constituents, it is hugely challenging to understand the rheological behaviour of the concrete mix. For this reason, it is necessary to thoroughly comprehend fresh property by understanding its rheology. The quality control and accurate prediction of the SCFRC rheology are crucial for the success of its production. A three-dimensional meshless smoothed particle hydrodynamics (SPH) computational approach, treating the SCFRC mix as a non-Newtonian Bingham fluid constitutive model has been coupled with the Lagrangian momentum and continuity equations to simulate the flow. The aim of this numerical simulation is to investigate the capabilities of the SPH methodology in predicting the flow and passing ability of SCFRC mixes through gaps in reinforcing bars. To confirm that the concrete mixes flow homogeneously, the distribution and orientation of steel fibres in the mixes have been simulated and compared against observations made in the laboratory experiments. It is revealed that the simulated flow behaviour of SCFRC compares well with results obtained in the laboratory tests

Assessing the effect of coarse aggregate size on self-compacting fibre reinforced concrete mix

Steel fibres increase inhomogeneity and alter rheological and hardened characteristics of self-compacting concrete. To investigate the rheological behaviour and hardened characteristics of self-compacting concrete (SCC) and self-compacting steel fibre reinforced concrete (SCSFRC), a wide range of normal strength self-compacting concrete mixes containing steel fibres and coarse aggregates (of size 10 mm, 20 mm) with target cube compressive strengths between 30 to 70 MPa were prepared in the laboratory. The plastic viscosity of these concrete mixes were estimated to be in the range between 20–50 Pa s , and the slump flow time t500 of each mix was recorded to ensure that the flow and passing ability for workability of the mixes satisfy the recommended British and European standards. This work mainly focuses on the properties of fibre reinforced self-compacting concrete containing 0.5% and 1% (by volume fraction) steel fibres and the effect of coarse aggregates on their rheological behaviour and flow characteristics. The effect of steel fibre content on the strength of hardened concrete is also investigated. In addition, comparison of flow behaviour between SCC and SCSFRC is also presented

Variational formulation of fractional step methods in SPH fluid mechanics applications

A fractional step projection method is introduced here to achieve incompressibility in the SPH method. Fractional step method is a popular approach used to solve incompressible fluid dynamics problems in traditional grid based methods and involves a two-step process to achieve incompressibility. Essentially, the velocity update over a time step is split into a component that does not take into account the divergence free condition, plus a pressure correction term which restores the incompressibility of the velocity. This paper mainly focuses on the variational formulation of fractional step method for SPH fluid applications by presenting a detailed description of the formulation of governing equations