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What’s Missing in Agile Hardware Design? Verification!

Journal of Computer Science & Technology 2023年第4期38卷 735-736页

作者： Babak Falsafi Parallel Systems Architecture Laboratory Institute of Computer and Communication SciencesSchool of Computer andCommunication SciencesEcole Polytechnique Fédérale de LausanneLausanneCH-1015Switzerland

Agile hardware design is an approach to developing hardware systems that draws inspiration from the principles and practices of agile software *** emphasizes collaboration,flexibility,iterative development,and quick adaptation to changing *** agile hardware design,the focus is on delivering functionalhardware systems in shorter development cycles while maintaining high-quality and customer *** particular,agile hardware design is of great interest in the open-source hardware ***-sourcehardware development—such as RISC-V—is at the forefront of initiatives to democratize hardware and drive innovation in chip design *** design is instrumental for the RISC-V community because it supportsrapid iteration,accommodates the evolving RISC-V standard and the addition of custom extensions,improvescommunity collaboration and time-to-market,and addresses the design challenges associated with complex architectural features.

关键词： hardware agile architectural

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A data-assisted physics-informed neural network(DA-PINN)for fretting fatigue lifetime prediction

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International Journal of Mechanical System Dynamics 2024年第3期4卷 361-373页

作者： Can Wang Qiqi Xiao Zhikun Zhou Yongyu Yang Gregor Kosec Lihua Wang Magd Abdel Wahab Soete Laboratory Department of Electrical EnergyMetalsMechanical Constructions and SystemsFaculty of Engineering and ArchitectureGhent UniversityGentBelgium Department of Engineering Mechanics School of Aerospace EngineeringHuazhong University of Science and TechnologyWuhanChina Key Laboratory for Mechanics Anhui Polytechnic UniversityWuhuChina Parallel and Distributed Systems Laboratory Jožef Stefan InstituteLjubljanaSlovenia School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghaiChina College of Engineering Yuan Ze UniversityTaiwanChina

In this study,we present for the first time the application of physics-informed neural network(PINN)to fretting fatigue *** PINN has recently been applied to pure fatigue lifetime prediction,it has not yet been explored in the case of fretting *** propose a data-assisted PINN(DA-PINN)for predicting fretting fatigue crack initiation *** traditional PINN that solves partial differential equations for specific problems,DA-PINN combines experimental or numerical data with physics equations as part of the loss function to enhance prediction *** DA-PINN method,employed in this study,consists of two main ***,damage parameters are obtained from the finite element method by using critical plane method,which generates a data set used to train an artificial neural network(ANN)for predicting damage parameters in other ***,the predicted damage parameters are combined with the experimental parameters to form the input data set for the DA-PINN models,which predict fretting fatigue *** results demonstrate that DA-PINN outperforms ANN in terms of prediction accuracy and eliminates the need for high computational costs once the damage parameter data set is ***,the choice of loss-function methods in DA-PINN models plays a crucial role in determining its performance.

关键词： crack initiation data-assisted fretting fatigue finite element method physics-informed neural network

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A multiscale finite element approach to analyse the effect of shot peening-induced surface roughness on fretting fatigue crack initiation

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Results in Engineering 2025年 26卷

作者： Li, Chao Han, Sutao Wang, Can Amanov, Auezhan Wang, Lihua Abdel Wahab, Magd Soete Laboratory Department of Electromechanical Systems and Metal Engineering Faculty of Engineering and Architecture Ghent University Finland Faculty of Engineering and Natural Sciences Tampere University Finland Department of Mechanical Engineering Sun Moon University Korea Republic of School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai200092 China College of Engineering Yuan Ze University Taiwan China Parallel and Distributed Systems Laboratory Jožef Stefan Institute Jamova cesta 39 LjubljanaSI-1000 Slovenia

Shot peening (SP) is a widely used surface treatment technique that enhances the mechanical performance of materials, notably improving fatigue resistance by inducing compressive residual stresses (RS) and modifying surface characteristics. While the overall benefits of SP on fatigue life are well-documented, the specific role of SP-induced surface roughness in fretting fatigue behaviour remains unclear. This study develops a multiscale framework based on finite element method (FEM) to isolate and quantify the influence of surface roughness resulting from SP on fretting fatigue. At the microscale, detailed FEM simulations are conducted to assess how surface topography affects local contact stresses, thereby extracting critical features brought by roughness. These features are then integrated into a macroscale model to construct a SP-treated model that accounts for the effects of surface roughness. Numerical results reveal that while surface roughness has a minimal effect on crack initiation location and orientation, it significantly affects crack initiation lifetime by redistributing contact stresses more favourably. Furthermore, incorporating experimentally measured roughness profiles into the numerical models enhances the accuracy of fatigue life predictions. These findings underscore the importance of considering surface roughness in numerical simulations to achieve reliable predictions of fretting fatigue behaviour in SP-treated materials. © 2025 The Authors

关键词： Residual stresses

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Fretting wear mechanism of GH4169 dovetail joint specimens treated with hybrid laser shock peening

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Tribology International 2025年 209卷

作者： Fang, Xiuyang Wang, Zheng Wahab, Magd Abdel Gong, Jianen Liu, Xiong Liu, Xing Cai, Zhenbing School of Mechanical Engineering Southwest Jiaotong University Chengdu610031 China Tribology Research Institute Key Lab of Advanced Technologies of Materials Southwest Jiaotong University Chengdu610031 China Soete Laboratory Department of Electrical Energy Metals Mechanical Constructions and Systems Faculty of Engineering and Architecture Ghent University Gent9000 Belgium College of Engineering Yuan Ze University Taiwan China Parallel and Distributed Systems Laboratory Jožef Stefan Institute Jamova cesta 39 LjubljanaSI-1000 Slovenia DongFang Electric Machinery Co. LTD Deyang618000 China State Key Laboratory of Advanced Electromagnetic Technology Huazhong University of Science and Technology Hubei Wuhan430074 China

Aero engine blade structure is prone to severe fretting wear under centrifugal forces and vibration loads, resulting in greatly reduced engine service life, which is a typical fretting damage problem. In this paper, without Absorbing layer Nanosecond Laser Shock Peening (wAN-LSP) and without Absorbing layer Nanosecond superimposed Femtosecond hybrid Laser Shock Peening (NF-LSP) are utilized to strengthen the surface of GH4169 dovetail joint specimens, which is a common material for engine blades, to explore its strengthening mechanism and fretting wear evolution law. The findings indicate that the surface roughness of the wAN-LSP specimen rises from 0.28 μm to 1.16 μm. The thermal effects of wAN-LSP lead to the formation of a molten layer roughly 10.97 μm thick on the surface, accompanied by numerous pits, ablation holes, and micro-cracks. In contrast, NF-LSP treatment effectively eliminates the surface oxidation defects made by the thermal effects of wAN-LSP, leading to a slight decrease in surface roughness. Both wAN-LSP and NF-LSP treatments enhance the surface hardness of the specimens, creating a plastic deformation layer roughly 400 μm deep, but the near surface hardness of NF-LSP treated specimen is further improved compared to that of the wAN-LSP specimen. The wear mechanism observed in the GH4169 dovetail joint specimens following wAN-LSP and NF-LSP treatment are identified as abrasive wear and oxidation wear. Initially, as the number of cycles raises, the wear volume of GH4169 specimen treated with wAN-LSP is higher than that of untreated specimen, but subsequently, it becomes lesser than that of the untreated specimen. This phenomenon results from the interplay between the molten layer and hardened layer. In the initial stage of wear, despite the surface strengthening of the wAN-LSP specimen, the presence of molten layer significantly diminishes the fretting wear resistance of the material. As wear progresses, the molten layer is removed, revealing the be

关键词： Abrasion

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Higher-Order Kinematics Modeling of 3-RRS parallel Mechanism Based on CGA

Research Square

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Research Square 2020年

作者： Wang, Chang Zhao, Tie-Shi Li, Er-Wei Zhao, Yan-Zhi Bian, Hui Geng, Ming-Chao Parallel Robot and Mechatronic System Laboratory Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao066004 China School of Mechanical Engineering Hebei University of Architecture Zhangjiakou075000 China

Higher-order kinematics of mechanisms has been applied in servo motor control, human-robot interaction and machinery life design fields, etc. The representations of acceleration and jerk by screws have been fully developed by researchers with the methods of the differential of the matrix representation of SE(3) group. Clifford algebra, which is tighter and with higher computational efficiency than the matrix method, is another representation of the motions of rigid bodies. It has been used in position kinematics, grub task motion planning, and robot vision for its convenience of geometric representations and calculations. As far as we know, the work of higher-order kinematics of mechanisms based on Clifford algebra is rare. First, after recalling the based theory of motion representation in conformal geometric algebra (CGA), the mathematical relationships between flag and motor are built. Second, a method for the higher-order kinematics modeling of serial chain mechanisms is proposed. Finally, the higher-order kinematics of the 3-RRS parallel mechanism is built to prove the correctness of the algorithm. This work further enriches the application of CGA for the higher-order kinematics modeling of parallel mechanisms. © 2020, CC BY.

关键词： Kinematics

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On the effect of out-of-phase cyclic normal load and axial stress ratios on fretting fatigue crack initiation and propagation

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International Journal of Solids and Structures 2025年 320卷

作者： Can Wang Qiqi Xiao Dagang Wang Zhenbing Cai Lihua Wang Gregor Kosec Magd Abdel Wahab Soete Laboratory Department of Electrical energy metals mechanical constructions and systems Faculty of Engineering and Architecture Ghent University Belgium School of Mechanical and Electrical Engineering China University of Mining and Technology Xuzhou 221116 China Tribology Research Institute Southwest Jiaotong University Chengdu 610031 China School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai 200092 China Parallel and Distributed Systems Laboratory Jožef Stefan Institute Jamova cesta 39 SI-1000 Ljubljana Slovenija College of Engineering Yuan Ze University Taiwan China

In this paper, we present a novel investigation into the influence of out-of-phase cyclic normal load and axial stress ratios on fretting fatigue crack initiation and propagation behaviours. Unlike previous studies that primarily focus on constant normal load, our research employs advanced numerical models to provide for the first time a detailed analysis of the effect of out-of-phase cyclic normal load on fretting fatigue crack initiation and propagation behaviours. Due to the non-proportional loading conditions, the frequency of loading, normal load ratio, and cyclic stress ratio play important roles in both crack initiation and propagation phases, which are not yet fully understood. Some experimental results reflect the effect of normal load ratio and cyclic stress ratio on the total fretting fatigue lifetime and wear scar, but there are no direct conclusions. This paper uses the Critical Plane Method and the Theory of Critical Distance to estimate crack initiation behaviour and lifetime. At the same time, the Extended Maximum Tangential Stress criterion from Linear Elastic Fracture Mechanics theory is applied to analyse the impact of load stress ratio on crack propagation path and lifetime, saving experimental time through numerical modelling. The enhancement ratios of crack propagation lifetime are less significant than those of crack initiation lifetime with varying axial stress ratios. Moreover, the impact of the stress ratio of both loads shows discrepancies under high and low cycle fatigue regimes.

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A modified low cycle fatigue Chaboche model for irradiation hardening behaviour of EUROFER97 at elevated temperatures

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European Journal of Mechanics - A/Solids 2025年 114卷

作者： Jianxin Liu Xiaowei Wang Aleksandr Zinovev Dmitry Terentyev Lihua Wang Magd Abdel Wahab Soete Laboratory Department of Electrical Energy Metals Mechanical Constructions and Systems Faculty of Engineering and Architecture Ghent University 9000 Ghent Belgium School of Mechanical and Power Engineering Nanjing Tech University Nanjing 211816 China Reliability Centered Manufacturing Research Institute Nanjing Tech University Nanjing 211816 China Structural Materials Group Institute for Nuclear Energy Technology Belgian Nuclear Research Centre SCK CEN 2400 Mol Belgium School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai 200092 China Parallel and Distributed Systems Laboratory Jožef Stefan Institute Jamova cesta 39 SI-1000 Ljubljana Slovenia College of Engineering Yuan Ze University Taiwan Republic of China

This study investigates the irradiation hardening mechanical behaviour of EUROFER97, a Reduced Activation Ferritic/Martensitic (RAFM) steel, using a modified Chaboche model within the temperature range of 250–350 °C. Structural materials for nuclear fusion reactors must maintain their performance under neutron irradiation. However, EUROFER97 faces challenges such as irradiation-induced hardening and embrittlement at irradiation temperatures below 350 °C, which lead to reduced ductility and toughness. This research incorporates an irradiation hardening factor into a modified Chaboche constitutive model to accurately simulate EUROFER97's behaviour under irradiation. A unified viscoplastic model is employed for finite element analysis, with variable parameters used to better represent the material's stress-strain evolution during cyclic loading and irradiation-induced hardening. Simulations are conducted using ABAQUS, with a UMAT subroutine developed to simulate fatigue, and a hybrid acceleration strategy is adopted to accelerate the calculation of different stages of Low Cycle Fatigue (LCF). Key findings demonstrate that the modified Chaboche model effectively predicts the irradiation hardening and cyclic softening behaviour of EUROFER97 under various irradiation doses and strain amplitudes. The model's predictions are in good agreement with experimental data, capturing the stress-strain hysteresis loops and irradiation-induced changes in mechanical properties, thereby validating its applicability not only to EUROFER97 but also to other nuclear structural materials, such as F82H ferritic/martensitic steel. The contribution of this study lies in refining the Chaboche model by incorporating irradiation effects, providing a robust tool for predicting the mechanical behaviour of structural materials under irradiation, which is crucial for the safety and design of fusion reactor components.

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parallel-in-Time Multi-Level Integration of the Shallow-Water Equations on the Rotating Sphere

arXiv

引用

arXiv 2019年

作者： Hamon, François P. Schreiber, Martin Minion, Michael L. Center for Computational Sciences and Engineering Lawrence Berkeley National Laboratory Berkeley United States Chair of Computer Architecture and Parallel Systems Technical University of Munich Germany Department of Applied Mathematics Lawrence Berkeley National Laboratory Berkeley United States

The modeling of atmospheric processes in the context of weather and climate simulations is an important and computationally expensive challenge. The temporal integration of the underlying PDEs requires a very large number of time steps, even when the terms accounting for the propagation of fast atmospheric waves are treated implicitly. Therefore, the use of parallel-in-time integration schemes to reduce the time-to-solution is of increasing interest, particularly in the numerical weather forecasting field. We present a multi-level parallel-in-time integration method combining the parallel Full Approximation Scheme in Space and Time (PFASST) with a spatial discretization based on Spherical Harmonics (SH). The iterative algorithm computes multiple time steps concurrently by interweaving parallel high-order fine corrections and serial corrections performed on a coarsened problem. To do that, we design a methodology relying on the spectral basis of the SH to coarsen and interpolate the problem in space. The methods are evaluated on the shallow-water equations on the sphere using a set of tests commonly used in the atmospheric flow community. We assess the convergence of PFASST-SH upon refinement in time. We also investigate the impact of the coarsening strategy on the accuracy of the scheme, and specifically on its ability to capture the high-frequency modes accumulating in the solution. Finally, we study the computational cost of PFASST-SH to demonstrate that our scheme resolves the main features of the solution multiple times faster than the serial schemes. Copyright © 2019, The Authors. All rights reserved.

关键词： Harmonic analysis

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Kinematic and Dynamic Modeling of parallel-serial Hybrid Stabilizing Crane Mechanism

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Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery 2018年第8期49卷 411-419and49页

作者： Li, Erwei Zhao, Tieshi Hu, Qiangqiang Wang, Chang Geng, Mingchao Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System Laboratory Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education Yanshan University Qinhuangdao066004 China College of Mechanical Engineering Hebei University of Architecture Zhangjiakou075000 China

Stabilizing crane plays an important role in the lifting of cargo between ships and offshore platforms, such as wind turbine and drilling platform under high sea conditions. According to the characteristics of motion compensation offshore, a parallel-serial hybrid stabilizing crane mechanism was proposed. The parallel part is a two degrees of freedom (DOF) rotational parallel mechanism (RPM), which has two continuously rotational DOF. The parallel part, with a virtual continuous axis, can isolate the impact of the rolling and pitching of the moored ship to provide a stable base for the serial part: PRRP kinematic chain. The serial part has the degree of heave, yaw, tilt and telescope. The whole stabilizing crane can keep the end point of the crane staying still relative to the earth. Firstly, the hybrid mechanism was described and the corresponding coordinate systems were established. Then, assuming the parallel part and the first P kinematic pair of the serial part compensated the motion of the moored ship, in the non-inertial system, combined the vector method and screw velocity and acceleration theories, the kinematic model of end of the stable gangway stabilizing at a fixed point was established in accordance with the sequence of the parallel part and the serial part. Based on Newton-Euler formulas in screw form and combined D'Alembert principle and virtual work principle, the dynamic model of the hybrid mechanism was established in accordance with the sequence of the serial part and the parallel part. Finally, the correctness of the models was verified by a numerical example. The work laid a theoretical foundation for the engineering application of the stabilizing crane. © 2018, Chinese Society of Agricultural Machinery. All right reserved.

关键词： Kinematics

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Multi-level spectral deferred corrections scheme for the shallow water equations on the rotating sphere

arXiv

引用

arXiv 2018年

作者： Hamona, François P. Schreiberb, Martin Miniond, Michael L. Center for Computational Sciences and Engineering Lawrence Berkeley National Laboratory Berkeley United States Department of Mathematics/Computer Science University of Exeter Exeter United Kingdom Computer Architecture and Parallel Systems Technical University of Munich Germany Department of Applied Mathematics Lawrence Berkeley National Laboratory Berkeley United States

Effcient time integration schemes are necessary to capture the complex processes involved in atmospheric ows over long periods of time. In this work, we propose a high-order, implicit-explicit numerical scheme that combines Multi-Level Spectral Deferred Corrections (MLSDC) and the Spherical Harmonics (SH) transform to solve the wave-propagation problems arising from the shallow-water equations on the rotating *** iterative temporal integration is based on a sequence of corrections distributed on coupled spacetime levels to perform a significant portion of the calculations on a coarse representation of the problem and hence to reduce the time-to-solution while preserving accuracy. In our scheme, referred to as MLSDCSH, the spatial discretization plays a key role in the efficiency of MLSDC, since the SH basis allows for consistent transfer functions between space-time levels that preserve important physical properties of the *** study the performance of the MLSDC-SH scheme with shallow-water test cases commonly used in numerical atmospheric modeling. We use this suite of test cases, which gradually adds more complexity to the nonlinear system of governing partial differential equations, to perform a detailed analysis of the accuracy of MLSDC-SH upon renement in time. We illustrate the stability properties of MLSDC-SH and show that the proposed scheme achieves up to eighth-order convergence in time. Finally, we study the conditions in which MLSDC-SH achieves its theoretical speedup, and we show that it can significantlyreduce the computational cost compared to single-level Spectral Deferred Corrections (SDC). Copyright © 2018, The Authors. All rights reserved.

关键词： Harmonic analysis

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