An improved material point method for coining simulation

Xu, Jiangping; Chen, Xiaotian; Zhong, Wen; Wang, Fei; Zhang, Xianglei

doi:10.1016/j.ijmecsci.2020.106258

Cited by 5 publications

(6 citation statements)

References 43 publications

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“…The process of imprint forming can be considered a quasi-static procedure [1,19,20]. Consequently, we can describe it by using the following governing equation:…”

Section: Dynamic Explicit Central Difference Algorithmmentioning

confidence: 99%

MPI/OpenMP-Based Parallel Solver for Imprint Forming Simulation

Li,

Xu,

Liu

et al. 2024

CMES

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In this research, we present the pure open multi-processing (OpenMP), pure message passing interface (MPI), and hybrid MPI/OpenMP parallel solvers within the dynamic explicit central difference algorithm for the coining process to address the challenge of capturing fine relief features of approximately 50 microns. Achieving such precision demands the utilization of at least 7 million tetrahedron elements, surpassing the capabilities of traditional serial programs previously developed. To mitigate data races when calculating internal forces, intermediate arrays are introduced within the OpenMP directive. This helps ensure proper synchronization and avoid conflicts during parallel execution. Additionally, in the MPI implementation, the coins are partitioned into the desired number of regions. This division allows for efficient distribution of computational tasks across multiple processes. Numerical simulation examples are conducted to compare the three solvers with serial programs, evaluating correctness, acceleration ratio, and parallel efficiency. The results reveal a relative error of approximately 0.3% in forming force among the parallel and serial solvers, while the predicted insufficient material zones align with experimental observations. Additionally, speedup ratio and parallel efficiency are assessed for the coining process simulation. The pure MPI parallel solver achieves a maximum acceleration of 9.5 on a single computer (utilizing 12 cores) and the hybrid solver exhibits a speedup ratio of 136 in a cluster (using 6 compute nodes and 12 cores per compute node), showing the strong scalability of the hybrid MPI/OpenMP programming model. This approach effectively meets the simulation requirements for commemorative coins with intricate relief patterns.

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“…The process of imprint forming can be considered a quasi-static procedure [1,19,20]. Consequently, we can describe it by using the following governing equation:…”

Section: Dynamic Explicit Central Difference Algorithmmentioning

confidence: 99%

MPI/OpenMP-Based Parallel Solver for Imprint Forming Simulation

Li,

Xu,

Liu

et al. 2024

CMES

View full text Add to dashboard Cite

show abstract

“…Moreover, the time-consuming algorithms in the solver, such as constitutive updating and remeshing, can be accelerated or even eliminated by using machine learning [8] and material point method [9].…”

Section: Introductionmentioning

confidence: 99%

An accelerated simulating method for flow forming process through locally and dynamically rigidifying the workpiece

Dong¹,

Zhan

Lyu³

et al. 2023

Preprint

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Flow forming is a widely used process for manufacturing tubular parts in the aerospace and defense industries. In this process, the workpiece is produced locally and continuously under the action of mandrel and feed of roller(s), which requires a lengthy finite element simulation (FES) time. To speed up the FES, dynamic rigidifying the portion of workpiece which undergoes little or no deformation is an available method to reduce the amount of calculation. The mobile region that deforms plastically during the process can be identified based on the position of the roller(s) and then projected onto the designed workpiece to construct the rigid-flexible coupling model. This identification can be accelerated by clustering the elements of workpiece into a sequence of blocks along the axial or hoop direction, or both. Thus, the workpiece can be subdivided into blocks or simply into rigid and deformable parts along the intersections of the blocks. In addition, the partitioned workpiece is overlaid by a structured mesh to store the historical data during process and ensure accuracy. By integrating the above methods, the local and dynamic rigidification method can be applied to simulate the flow forming process via the secondary development of Abaqus. Comparing the precision and efficiency of models divided along diverse directions, the model divided along the axes has the optimal performance and can reduce the calculation time by 1/4 to 1/3. When the workpiece is cut only at the interfaces between rigid and deformable parts, the FES results for the large radius model show that rigidification performs well with large reduction.

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“…The micro-cracks and potential failure areas of commemorative coins are often judged by the experience of technicians. Therefore, more and more scholars adopt upper bound methods [1][2][3][4] and numerical methods to study the stamping process of bimaterial coins [5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, numerical methods has been employed in coining process to assist engineers to get a better understanding of the upper bound methods and their experiences, especially in bi-material coining [5,6,8,[10][11][12]22]. Marques and Martins used the rigid plastic formula to simulate the joint of bi-metallic coins [23].…”

Section: Introductionmentioning

confidence: 99%

“…Altinbalik et al used the modified upper bound solution containing dimensionless optimization parameters to evaluate the forming load of cylindrical profile [27]. Overcoming the extreme small time step in explicit finite element method, Xu et al proposed an improved material point method to predict the filling shortage in the coining process, and its performance was verified by the experimental results [12]. Although many researches have been done in the field of coining process to produce bi-material coins, the origins of sprout of micro-crack and dropping of inner core are still in exploring.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Predictions of stress distribution and material flow in coining process for bi-material commemorative coin

Peng¹,

Xu²,

Wang³

2022

Mater. Res. Express

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Bi-material commemorative coins have the characteristics of weight reduction, beauty and corrosion resistance. However, due to different characteristics of bi-materials, defects such as stress concentration, drop of inner core and micro-cracks often occur at interface of materials in usage. Engineers usually employ multiple mold trials to check the bonding state of two material regions, judge the stress concentration area and modify the process to avoid micro-crack sprout. Based on the professional metal forming software Deform 3D, stress distribution and material flow in coining processes for single and bi- material commemorative coins are studied. Numerical examples demonstrate that there are three typical stages over the whole process whether the coin is single or bi- material. And stress concentrations appear at the corners of upper/lower dies and the material interface in case of bi-material. The former concentration lead to sprout of micro-cracks along the shear bands and the latter triggers cracks at the interface. In addition, two materials with different hardness are adopted in the core and ring, respectively, to investigate the mutual interaction behavior at interface. Numerical findings indicate that large strains occur at the edge and the interface in case of bi-material with soft core. These imply that deep adhesion happens at the interface in case of that soft material is in the core. It suggests that hard material in the inner core and soft one in the outer ring may cause falling of the core.

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An improved material point method for coining simulation

Cited by 5 publications

References 43 publications

MPI/OpenMP-Based Parallel Solver for Imprint Forming Simulation

MPI/OpenMP-Based Parallel Solver for Imprint Forming Simulation

An accelerated simulating method for flow forming process through locally and dynamically rigidifying the workpiece

Predictions of stress distribution and material flow in coining process for bi-material commemorative coin

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