Material point method simulations of transverse fracture in wood with realistic morphologies

Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 375-381 ◽  
Author(s):  
John A. Nairn

Abstract A new numerical method called the material point method (MPM) is well suited for modeling problems with complex geometries and with crack propagation in arbitrary directions. In this paper, these features of MPM were used to simulate transverse fracture in solid wood. The simulations were run on the scale of growth rings. The ease with which MPM handles complex geometries was helpful for modeling realistic morphologies of earlywood and latewood. Because MPM discretizes a body into material points, it was possible to go directly from a digital image of wood to a numerical model by assigning the location and properties of material points based on the intensity or color of pixels in an image. Because the description of cracks in MPM is meshless, it can handle a variety of crack propagation and direction criteria and can simulate complex crack paths that are a consequence of the morphology of the specimen. MPM simulations were run for cracks in the radial direction, the tangential direction, and at two angles to the radial direction. The specimens were loaded by axial displacement or by wedge opening. The MPM simulations fully included contact effects during wedge loading. Finally, the potential for coupling such simulations to new experiments as a tool for characterization of wood is discussed.

2021 ◽  
Vol 14 (12) ◽  
pp. 7749-7774
Author(s):  
Emmanuel Wyser ◽  
Yury Alkhimenkov ◽  
Michel Jaboyedoff ◽  
Yury Y. Podladchikov

Abstract. We propose an explicit GPU-based solver within the material point method (MPM) framework using graphics processing units (GPUs) to resolve elastoplastic problems under two- and three-dimensional configurations (i.e. granular collapses and slumping mechanics). Modern GPU architectures, including Ampere, Turing and Volta, provide a computational framework that is well suited to the locality of the material point method in view of high-performance computing. For intense and non-local computational aspects (i.e. the back-and-forth mapping between the nodes of the background mesh and the material points), we use straightforward atomic operations (the scattering paradigm). We select the generalized interpolation material point method (GIMPM) to resolve the cell-crossing error, which typically arises in the original MPM, because of the C0 continuity of the linear basis function. We validate our GPU-based in-house solver by comparing numerical results for granular collapses with the available experimental data sets. Good agreement is found between the numerical results and experimental results for the free surface and failure surface. We further evaluate the performance of our GPU-based implementation for the three-dimensional elastoplastic slumping mechanics problem. We report (i) a maximum 200-fold performance gain between a CPU- and a single-GPU-based implementation, provided that (ii) the hardware limit (i.e. the peak memory bandwidth) of the device is reached. Furthermore, our multi-GPU implementation can resolve models with nearly a billion material points. We finally showcase an application to slumping mechanics and demonstrate the importance of a three-dimensional configuration coupled with heterogeneous properties to resolve complex material behaviour.


2019 ◽  
Author(s):  
Krishna Kumar ◽  
Jeffrey Salmond ◽  
Shyamini Kularathna ◽  
Christopher Wilkes ◽  
Ezra Yoanes Setiasabda ◽  
...  

In this paper, we describe a new scalable and modular material point method (MPM) code developed for solving large-scale problems in continuum mechanics. The MPM is a hybrid Eulerian-Lagrangian approach, which uses both moving material points and computational nodes on a background mesh. The MPM has been successfully applied to solve large-deformation problems such as landslides, failure of slopes, concrete flows, etc. Solving these large-deformation problems result in the material points actively moving through the mesh. Developing an efficient parallelisation scheme for the MPM code requires dynamic load-balancing techniques for both the material points and the background mesh. This paper describes the data structures and algorithms employed to improve the performance and portability of the MPM code.


2021 ◽  
Vol 245 ◽  
pp. 107602
Author(s):  
Sha Li ◽  
Yun Zhang ◽  
Jichun Wu ◽  
Jun Yu ◽  
Xulong Gong

2012 ◽  
Vol 525-526 ◽  
pp. 513-516 ◽  
Author(s):  
Irene Guiamatsia ◽  
Giang D. Nguyen

Modern numerical techniques utilised to model crack propagation tend to be optimized for tracking the evolution of a single crack. Real fracture processes are however complex, involving the initiation and propagation of opening (activated) cracks, while other may close (deactivate) and undergo frictional dissipations. Accounting for the correct loss of energy (through debonding and friction) is essential to achieving a realistic description of the fracture process. One common strategy has been to make small adaptations to traditional techniques to tackle multiple cracking, in effect relying on extensive complicated computational algorithms. A typical example is the use of cohesive models in combination with the eXtended finite Element method where cracks, sometimes intersecting, need to be defined explicitly. In this study the Material Point Method is used for the analysis of fracture propagation. Crack states, as internal variables, are stored within the material points and mapped as strong discontinuities to the elements during the Lagrangian phase of the solution. Consequently, material points carrying cracks of different sizes and orientations are allowed to cohabit within the same element, yielding a natural description of the fracture/fragmentation process. The three-point bending test is used to demonstrate the features of the new approach.


2021 ◽  
Author(s):  
Emmanuel Wyser ◽  
Yury Alkhimenkov ◽  
Michel Jaboyedoff ◽  
Yury Y. Podladchikov

Abstract. We propose an explicit GPU-based solver within the material point method (MPM) framework on a single graphics pro- cessing unit (GPU) to resolve elastoplastic problems under two- and three-dimensional configurations (i.e., granular collapses and slumping mechanics). Modern GPU architectures, including Ampere, Turing and Volta, provide a computational framework that is well suited to the locality of the material point method in view of high-performance computing. For intense and nonlocal computational aspects (i.e., the back-and-forth mapping between the nodes of the background mesh and the material points), we use straightforward atomic operations (the scattering paradigm). We select the generalized interpolation material point method (GIMPM) to resolve the cell-crossing error, which typically arises in the original MPM, because of the C0 continuity of the linear basis function. We validate our GPU-based in-house solver by comparing numerical results for granular collapses with the available experimental data sets. Good agreement is found between the numerical results and experimental results for the free surface and failure surface. We further evaluate the performance of our GPU-based implementation for the three-dimensional elastoplastic slumping mechanics problem. We report i) a maximum performance gain of x200 between a CPU- and GPU-based implementation, provided that ii) the hardware limit (i.e., the peak memory bandwidth) of the device is reached. We finally showcase an application to slumping mechanics and demonstrate the importance of a three-dimensional configuration coupled with heterogeneous properties to resolve complex material behaviour.


Author(s):  
Xuchen Han ◽  
Theodore F. Gast ◽  
Qi Guo ◽  
Stephanie Wang ◽  
Chenfanfu Jiang ◽  
...  

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