Pressboard is a cellulose-based material that constitutes a high-density network of cellulose fib... more Pressboard is a cellulose-based material that constitutes a high-density network of cellulose fibers, which is considerably thicker (more than 1 mm thick) and denser (with mass density between 800 and 1300 kg/m) than typical paper/board materials. Pressboard components have been widely used in e.g. power transformer applications, thanks to the excellent electrical insulation properties as well as good mechanical performance [1]. As a cellulose-based polymeric material, pressboard is however very sensitive to moisture and temperature, which affect the mechanical performance of the materials [2]. The present work is aimed at investigating the effects of moisture and temperature on the stationary and transient mechanical responses of pressboard.
Dynamic submarine cables are used to provide electrical power to floating oil/gas production plat... more Dynamic submarine cables are used to provide electrical power to floating oil/gas production platforms and to export power from marine renewable energy systems such as floating wind turbines. During installation and life-time operation, the dynamic power cable is subjected to various loads, e.g. axial tension, bending and torsion. A typical three-phase AC cable consist of three helically-interwound power cores with three polymeric fillers to accomplish a circular circumference over which sheaths and tensile armour layers are applied. The present paper focuses on the mechanical behaviour of a dynamic submarine cable subjected to a combined axial tension, radial pressure and bending load. Particular interest is emphasized on the stick-slip behaviour of the helically-interwound power cores. 3D finite element (FE) model has been developed, where the interactions on all layers of the cable are extrinsically taken into account. The stick-slip behaviour of the power cores and the resulting...
... By Denny Tjahjanto,* Sergio Turteltaub, Akke Suiker and Sybrand van der Zwaag ... A. For the ... more ... By Denny Tjahjanto,* Sergio Turteltaub, Akke Suiker and Sybrand van der Zwaag ... A. For the austenitic carbon concentrations indicated above, the magnitudes of the critical value of the effective isothermal driving force (ie, critical value for the total driving force minus the thermal ...
Micromechanically-based models are used to mimic the martensitic phase transformations in retaine... more Micromechanically-based models are used to mimic the martensitic phase transformations in retained austenite and the elasto-plastic behavior of the adjacent ferritic phase. The numerical simulations concern TRIP steel samples with a finite number of grains of ...
Archives of Computational Methods in Engineering, 2014
ABSTRACT While solid mechanics codes are now conventional tools both in industry and research, th... more ABSTRACT While solid mechanics codes are now conventional tools both in industry and research, the increasingly more exigent requirements of both sectors are fuelling the need for more computational power and more advanced algorithms. For obvious reasons, commercial codes are lagging behind academic codes often dedicated either to the implementation of one new technique, or the upscaling of current conventional codes to tackle massively large scale computational problems. Only in a few cases, both approaches have been followed simultaneously. In this article, a solid mechanics simulation strategy for parallel supercomputers based on a hybrid approach is presented. Hybrid parallelization exploits the thread-level parallelism of multicore architectures, combining MPI tasks with OpenMP threads. This paper describes the proposed strategy, programmed in Alya, a parallel multi-physics code. Hybrid parallelization is specially well suited for the current trend of supercomputers, namely large clusters of multicores. The strategy is assessed through transient non-linear solid mechanics problems, both for explicit and implicit schemes, running on thousands of cores. In order to demonstrate the flexibility of the proposed strategy under advance algorithmic evolution of computational mechanics, a non-local parallel overset meshes method (Chimera-like) is implemented and the conservation of the scalability is demonstrated.
Pressboard is a cellulose-based material that constitutes a high-density network of cellulose fib... more Pressboard is a cellulose-based material that constitutes a high-density network of cellulose fibers, which is considerably thicker (more than 1 mm thick) and denser (with mass density between 800 and 1300 kg/m) than typical paper/board materials. Pressboard components have been widely used in e.g. power transformer applications, thanks to the excellent electrical insulation properties as well as good mechanical performance [1]. As a cellulose-based polymeric material, pressboard is however very sensitive to moisture and temperature, which affect the mechanical performance of the materials [2]. The present work is aimed at investigating the effects of moisture and temperature on the stationary and transient mechanical responses of pressboard.
Dynamic submarine cables are used to provide electrical power to floating oil/gas production plat... more Dynamic submarine cables are used to provide electrical power to floating oil/gas production platforms and to export power from marine renewable energy systems such as floating wind turbines. During installation and life-time operation, the dynamic power cable is subjected to various loads, e.g. axial tension, bending and torsion. A typical three-phase AC cable consist of three helically-interwound power cores with three polymeric fillers to accomplish a circular circumference over which sheaths and tensile armour layers are applied. The present paper focuses on the mechanical behaviour of a dynamic submarine cable subjected to a combined axial tension, radial pressure and bending load. Particular interest is emphasized on the stick-slip behaviour of the helically-interwound power cores. 3D finite element (FE) model has been developed, where the interactions on all layers of the cable are extrinsically taken into account. The stick-slip behaviour of the power cores and the resulting...
... By Denny Tjahjanto,* Sergio Turteltaub, Akke Suiker and Sybrand van der Zwaag ... A. For the ... more ... By Denny Tjahjanto,* Sergio Turteltaub, Akke Suiker and Sybrand van der Zwaag ... A. For the austenitic carbon concentrations indicated above, the magnitudes of the critical value of the effective isothermal driving force (ie, critical value for the total driving force minus the thermal ...
Micromechanically-based models are used to mimic the martensitic phase transformations in retaine... more Micromechanically-based models are used to mimic the martensitic phase transformations in retained austenite and the elasto-plastic behavior of the adjacent ferritic phase. The numerical simulations concern TRIP steel samples with a finite number of grains of ...
Archives of Computational Methods in Engineering, 2014
ABSTRACT While solid mechanics codes are now conventional tools both in industry and research, th... more ABSTRACT While solid mechanics codes are now conventional tools both in industry and research, the increasingly more exigent requirements of both sectors are fuelling the need for more computational power and more advanced algorithms. For obvious reasons, commercial codes are lagging behind academic codes often dedicated either to the implementation of one new technique, or the upscaling of current conventional codes to tackle massively large scale computational problems. Only in a few cases, both approaches have been followed simultaneously. In this article, a solid mechanics simulation strategy for parallel supercomputers based on a hybrid approach is presented. Hybrid parallelization exploits the thread-level parallelism of multicore architectures, combining MPI tasks with OpenMP threads. This paper describes the proposed strategy, programmed in Alya, a parallel multi-physics code. Hybrid parallelization is specially well suited for the current trend of supercomputers, namely large clusters of multicores. The strategy is assessed through transient non-linear solid mechanics problems, both for explicit and implicit schemes, running on thousands of cores. In order to demonstrate the flexibility of the proposed strategy under advance algorithmic evolution of computational mechanics, a non-local parallel overset meshes method (Chimera-like) is implemented and the conservation of the scalability is demonstrated.
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Papers by Denny Tjahjanto