In this article, the presented work aims to scavenge maximum electrical outputs by using the novel microelectromechanical system flared-U shaped spring based piezoelectric vibration energy harvester ...(PVEH). The performance studies were carried out by employing four different variations of lead zirconate titanate (PZT) piezoelectric material namely PZT-4, PZT-5A, PZT-5H, and PZT-8 in the same size and shape of the proposed device. The maximum output powers employing PZT-4, PZT-5A, PZT-5H, and PZT-8 piezoelectric materials are 7.156 nW, 8.657 nW, 10.738 nW, 5.701 nW over 30 Hz, 28.4 Hz, 28.6 Hz, and 30.2 Hz, resonant frequency, respectively, at input acceleration of 0.07 g. From the finite element method simulator COMSOL Multiphysics 5.4 (licensed version) simulation-based outcomes, it is inferred that PZT-5H piezoelectric material performs better than other variations of PZT, such as PZT-4, PZT-5A, and PZT-8 piezoelectric materials.
We propose a partially penalized P1/CR immersed finite element (IFE) method with midpoint values on edges as degrees of freedom for CR elements to solve planar elasticity interface problems. Optimal ...approximation errors in L2 norm and H1 semi‐norm are obtained for the P1/CR IFE spaces. Moreover, by adding some stabilization terms on the edges of interface elements, we derive an optimal error estimate for the P1/CR IFE method. Our method differs from the method with average values on edges as degrees of freedom for P1/CR elements in Qin et al.'s study, where no approximation theoretical result was presented. Numerical examples confirm our theoretical results.
Fiber reinforced polymer (FRP) composite materials produced by pultrusion technique attract the attention of researchers due to their superior properties. Limited studies are available in the ...literature where experimental and theoretical investigations on the FRP composites are carried out together. In this study, the flexure performances of pultruded glass FRP (P-GFRP) composite beams were investigated experimentally and theoretically. Theoretical approaches for flexural analysis of P-GFRP composite beams were developed with the help of variational methods. Kinematic relations of composite beams were defined based on high order shear deformation beam theory. Effective material properties of composite beams were obtained by using mixture rule model. The differential field equations were transformed to functional with Gâteaux differential method. The element matrix with a total of 10 degrees of freedom was obtained by using the mixed finite element method (MFEM). Moreover, classical finite element modeling (FEM) was performed with the help of ABAQUS program. Various beam specimens with different fiber orientations were extracted from the P-GFRP box profile. Tensile and burnout tests were performed to determine the mechanical properties of the obtained P-GFRP composite beam specimens. Three-point bending test was utilized to investigate flexure performance. Kinetic, macro and micro mechanical damage analyzes were performed to better understand the behavior of the P-GFRP composite beams. Experimental results, theoretical solution results and FEM simulation results were compared and numerical values were found to be very close to each other.
The aim of this paper is to analyze the integration for 3D isogeometric finite element method solvers and its effective scheduling on hierarchical computer architecture. Data necessary for ...concurrency over elements is independent, so computation on this level is trivially concurrent. However, constructing several layers of concurrency for the integration algorithm is challenging. In this work, we propose a multilevel concurrent integration algorithm associated with scheduling that brings one extra degree of possible speedup. Because of one extra degree of possible speedup, we analyze the concurrent integration inside elements. The scheduling algorithm is intended for strongly related hierarchical architectures of a GPU. Using trace theory and Foata Normal Form, we verify integrity of the proposed solution. Summing up, we propose a general method for analyzing concurrency of the integration algorithm. We instantiate this method on a classical element-based integration algorithm, however, this methodology is possible to apply for other integration algorithms, including sum factorization, fast numerical quadrature, or row-wise integration methods.
•Multilayer parallel integrating coefficients of IsoGeometric Analysis IGA equations.•Trace theory model used for the formal verification.•Dikert graph based sub-optimal scheduling on cluster with GPU units.•Efficiency and scalability tests of proposed parallel IGA for L2 projection problem.•Application to sum factorization, fast numerical quadrature, row-wise integration.
•MHD mixed convection nanofluid in a vented cavity with elastic walls is studied.•At higher Re, when E changes both deterioration and enhancement of Nu is observed.•The number of vortices is reduced ...when the strength of the magnetic field is increased•Both deterioration and enhancement of average Nu is obtained with increasing Ha.•Generally, a reduction of Nu is achieved with increment in number of steps.
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In this study, numerical analysis of mixed convection of CuO-water nanofluid in a cavity with inlet and outlet ports is performed under the effects of inclined magnetic field and step like corrugated elastic walls. The numerical simulation results are obtained by using finite element method. The Arbitrary-Lagrangian–Eulerian method is utilized for the description of the fluid motion with the elastic wall in the fluid-structure interaction model. In the current study, multiple step like corrugation of the wall is considered and it is made elastic which adds additional flexibility for the control of convective heat transfer features of the vented cavity. Effects of various pertinent parameters such as Reynolds number (between 100 and 500), Hartmann number (between 0 and 40), magnetic inclination angle (between 0° and 90°), elastic modulus of the flexible wall (between 5 × 104 and 108), number of step-like corrugation (between 1 and 8) and nanoparticle volume fraction (between 0 and 3%) on the fluid flow and heat transfer characteristics are numerically examined. It is observed that for higher value of Reynolds number, local Nusselt number both deteriorates and enhances in various locations along the hot wall whereas the changes in the local Nusselt number are marginal for lower value of Reynolds number. The multiple vortices in the vented cavity are influenced by the variation of magnetic field parameters and number of step like corrugation of the wall while the effects are not significant for the change of magnetic inclination angle. When the value of Hartmann number augments, the average heat transfer reduces until Hartmann number of 30 and increases for the highest value of Hartmann number. The average Nusselt number increment are in the range of 9-9.5% with the nanoparticle addition at the highest volume fraction in the absence and presence of magnetic field. Even though significant changes in the local Nusselt number are observed when the number of step like corrugation increases, it has a deterioration effect on the average heat transfer generally and 5.5% reduction in the average Nusselt number is obtained when the value is increased from 1 to 8.
This paper considers probabilistic slope stability analysis using the Random Finite Element Method (RFEM) combined with processes to determine the level of similarity between random fields. A ...procedure is introduced to predict the Factor of Safety (FoS) of individual Monte Carlo Method (MCM) random field instances prior to finite element simulation, based on random field similarity measures. Previous studies of probabilistic slope stability analysis have required numerous MCM instances to reach FoS convergence. However, the methods provided in this research drastically reduce computational processing time, allowing simulations previously considered too computationally expensive for MCM analysis to be simulated without obstacle. In addition to computational efficiency, the comparison based procedure is combined with cluster analysis methods to locate random field characteristics contributing to slope failure. Comparison measures are presented for slope geometries of an Australian open pit mine to consider the impacts of associated factors such as groundwater on random field similarity predictors, while highlighting the capacity of the similarity procedure for prediction, classification and computational efficiency.
The coupling of non-matching meshes is of great interest in the field of computational mechanics. It reduces meshing burden by allowing users to divide a problem domain into several simpler ...subdomains and generate meshes for them independently. In this paper, a coupling method using arbitrary polyhedron elements is presented. On the interface of two non-matching meshes, a new surface mesh of polygon elements is constructed by merging the non-matching meshes. A shifting procedure is designed to prevent the distortion of surface elements. The polyhedron elements connected to the interface are modified by replacing their faces on the interface with the new polygon elements, leading to matching discretization on the interface. The modified polyhedron elements are modeled by the scaled boundary finite element method and no further volume discretization is required. No interface constraints or special shape functions are required in the analysis. Seven numerical examples are presented to demonstrate the versatility and robustness of the proposed procedure. Convergence behavior is also examined.
•Non-matching meshes at their interfaces are converted to matching meshes using a polytree algorithm.•Polyhedron elements requiring on surface discretization are employed.•Displacements are conformable at the interfaces.•No interface constraints are required.•Applications facilitating the mesh generation of complex geometries are demonstrated.
This paper proposes a novel tubular double-stator vernier permanent-magnet (TDS-VPM) motor for artificial hearts. The key of the proposed motor is double-stator and vernier structures. Due to its ...vernier structure, more PMs can be adopted in the proposed TDS-VPM motor and the useful harmonics of the air-gap flux density are increased, thus improving thrust density. Furthermore, double stator, namely inner stator and outer stator, has an appropriate 90° (electrical degree) angle difference. Since the inner stator is located inside the mover, the motor space is fully used. Hence, the thrust density is enhanced and the axial direction length is reduced. Meanwhile, the angle difference between the inner and the outer stator can reduce the cogging force of this TDS-VPM motor. The electromagnetic characteristics of the proposed motor are analyzed using the time-stepping finite-element method, confirming the validity of the theoretical analysis.
Abstract
General relativistic magnetohydrodynamic (GRMHD) simulations have revolutionized our understanding of black hole accretion. Here, we present a GPU-accelerated GRMHD code H-AMR with ...multifaceted optimizations that, collectively, accelerate computation by 2–5 orders of magnitude for a wide range of applications. First, it introduces a spherical grid with 3D adaptive mesh refinement that operates in each of the three dimensions independently. This allows us to circumvent the Courant condition near the polar singularity, which otherwise cripples high-resolution computational performance. Second, we demonstrate that local adaptive time stepping on a logarithmic spherical-polar grid accelerates computation by a factor of ≲10 compared to traditional hierarchical time-stepping approaches. Jointly, these unique features lead to an effective speed of ∼10
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zone cycles per second per node on 5400 NVIDIA V100 GPUs (i.e., 900 nodes of the OLCF Summit supercomputer). We illustrate H-AMR's computational performance by presenting the first GRMHD simulation of a tilted thin accretion disk threaded by a toroidal magnetic field around a rapidly spinning black hole. With an effective resolution of 13,440 × 4608 × 8092 cells and a total of ≲22 billion cells and ∼0.65 × 10
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time steps, it is among the largest astrophysical simulations ever performed. We find that frame dragging by the black hole tears up the disk into two independently precessing subdisks. The innermost subdisk rotation axis intermittently aligns with the black hole spin, demonstrating for the first time that such long-sought alignment is possible in the absence of large-scale poloidal magnetic fields.
