Integrating Critical Multiliteracies Pedagogy in ESL/EFL Teaching

This article argues for enacting a synthesis of English language teaching (ELT) and critical pedagogy into what we call critical multiliteracies pedagogy (CMP) in the context of ESL/EFL teaching. CMP challenges and expands language and literacy instruction beyond a skills-based pedagogy to be inclusive of diverse modes, voices, and identities to address critical issues across local, global, and transnational contexts in ESL/EFL classrooms. Particularly, we share how an international professional development program has promoted CMP for 20 Korean English teachers working with adolescent multilingual learners in South Korea. Findings show how participating teachers critically reframed their vision of ELT, enacting and envisioning new ways of teaching English through CMP despite challenges at the systemic level. Implications discuss how TESOL professionals can integrate CMP into diverse ELT contexts, responding to the call to uptake powerful new ways to communicate and create knowledge and ideas for a more just society

Nonlinear thermoelastic topology optimization with the level-set method

This work presents level-set topology optimization of structures considering nonlinear thermoelasticity. To analyze a structure experiencing large thermoelastic loads, a stress-free deformation driven by temperature change is introduced by multiplicative decomposition of the mechanical and thermal deformations. The consistent design sensitivity and the strategy of obtaining optimal update velocity are presented. By incorporating the thermoelastic nonlinear-ity into the optimization scheme, the design space is widened because of the increased accuracy of the structural and sensitivity analysis at the higher loading conditions. To demonstrate the effect of the nonlinearity in the context of large-deforming structures, the end-compliance minimization problems are solved for a range of thermoelastic loads. Changes in the layouts for a given load are shown and discussed with regards to their structural behavior. The material layouts are shown to be designed in a way that a counteracting effect between thermal and mechanical loads is created. We also demonstrate that such a manipulation of the thermal loading path suppresses the mechanical deformation even up to snap-through instability. To further elucidate the effect of nonlinearity, the nonlinear layouts and their behaviors are compared with those obtained from the optimization that considers linear thermoelasticity only

Level set topology optimization for fluid-structure interactions

In this work a level set topology optimization (LSTO) method is developed in combination with a nodally integrated reproducing kernel particle method (RKPM) for solving fluid-structure interaction problems (FSI). FSI falls into a specific class of topology optimization problems known as design-depended. In this class the direction, magnitude and position of the loads depend on the structure itself. Thus, the main challenge lies in tracking the interface to correctly apply the loads and coupling conditions. The simplest class of design-dependent loading problems considering only hydrostatic pressure is addressed here, with the aim of extending the same methodology to viscous flows in the near future. The freedom RKPM offers to place particles anywhere in the domain in combination with the implicit boundary representation given by the level set method, provides an effective framework to handle the dendency of loading by moving the particles on the pressure boundary without the need of remeshing or special numerical treatments. Benchmarking examples involving both constant and variable pressure loads are solved to illustrate the applicability of the methodology. For the extension to viscous flows, we set up an initial framework that utilizes the modified immersed finite element method (mIFEM) through the opensource software OpenIFEM. With mIFEM the coupled equations can be solved efficiently on a fixed fluid grid, thus avoiding to remesh for the fluid, while the solid on top of the fluid is free to move and deform. Combining LSTO, RKPM and mIFEM, the optimized results obtained for hydrostatic pressure are placed in a viscous flow field to perform a transient analysis. The LSTO defines the geometry of the structure, the solid domain is analyzed using RKPM with the naturally stabilized nodal integration technique (NSNI) and mIFEM is used to solve the coupled equations on a fixed fluid mesh

Implementation of topology optimization using openMDAO

Topology optimization is one of the widely known branches among the structural optimization, and it distinguishes itself being able to generate extremely lightweight structures. Recently it has drawn particular interest from both industry and academia because of its natural applicability to additive manufacturing. However, its implementation is often a daunting task for engineers in practice. In particular there can potentially be a large programming effort required to modify the method, even from subtle tweaks in the problem definition or solution algorithm. Changes to the code can leave to corresponding updates to relevant derivative calculations, further compounding the problem. Implementation, therefore, is not only time-consuming but also repetitive and susceptible to human-induced errors. In this regard, topology optimization implementations stand to benefit from changes that result in more code modularity, ease of restructuring, and more automated derivative calculations. In this work we propose using OpenMDAO, a computational framework for multidisciplinary design optimization, as a generic platform for to built topology optimization implementations with in order to achieve these implementation improvements. Two widely used topology optimization techniques???density-based and level-set???are implemented as to serve as reference code designs. These techniques are implemented in a decomposed manner, with the aid of the modular architecture of OpenMDAO as well as state-of-the-art numerical methods. To demonstrate the flexibility of the new topology optimization architecture, two variations on the density-based topology optimization approach are shown

Openlsto: Open-source software for level set topology optimization

In this paper, we present an Open source software for Level Set based Structural Topology Optimization (OpenLSTO) written in C++. This software comes with two modules: an FEA module which can be used to perform finite element analysis, and an LSM module which can be used to perform design optimization using the level set method. OpenLSTO can be compiled and executed with just a C++ compiler, being independent of any third-party libraries. This first light version of OpenLSTO implements the level set topology optimization method for the compliance minimization problem, subject to a volume constraint. With the help of a user tutorial, we explain the layout of the code. We show how to implement the key stages of level set topology optimization using brief code snippets and relevant theory. In future versions of OpenLSTO, extended capabilities using external libraries are to be launched. The code can be downloaded from http://m2do.ucsd.edu/software/. ?? 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved