Abstract

The aim of this work is to present a new procedure for modelling industrial processes
that involve granular material flows, using a numerical model based on the Particle
Finite Element Method (PFEM). The numerical results herein presented show
the potential of this methodology when applied to different branches of industry.
Due to the phenomenological richness exhibited by granular materials, the present
work will exclusively focus on the modelling of cohesionless dense granular flows.

The numerical model is based on a continuum approach in the framework of
large-deformation plasticity theory. For the constitutive model, the yield function is
defined in the stress space by a Drucker-Prager yield surface characterized by two
constitutive parameters, the cohesion and the internal friction coefficient, and
equipped with a non-associative deviatoric flow rule. This plastic flow condition is
considered nearly incompressible, so the proposal is integrated in a u- p mixed
formulation with a stabilization of the pressure term via the Polynomial Pressure
Projection (PPP). In order to characterize the non-linear dependency on the shear
rate when flowing a visco-plastic regularization is proposed.

The numerical integration is developed within the Impl-Ex technique, which increases
the robustness and reduces the iteration number, compared with a typical
implicit integration scheme. The spatial discretization is addressed within the
framework of the PFEM which allows treating the large deformations and motions
associated to granular flows with minimal distortion of the involved finite element
meshes. Since the Delaunay triangulation and the reconnection process minimize
such distortion but do not ensure its elimination, a dynamic particle discretization of
the domain is proposed, regularizing, in this manner, the smoothness and particle
density of the mesh. Likewise, it is proposed a method that ensures conservation of
material or Lagrangian surfaces by means of a boundary constraint, avoiding in this
way, the geometric definition of the boundary through the classic -shape method.

For modelling the interaction between the confinement boundaries and granular
material, it is advocated for a method, based on the Contact Domain Method (CDM)
that allows coupling of both domains in terms of an intermediate region connecting
the potential contact surfaces by a domain of the same dimension than the contacting
bodies. The constitutive model for the contact domain is posed similarly to that for
the granular material, defining a correct representation of the wall friction angle.
In order to validate the numerical model, a comparison between experimental
results of the spreading of a granular mass on a horizontal plane tests, and finite
element predictions, is carried out. These sets of examples allow us validating the
model according to the prediction of the different kinematics conditions of granular
materials while spreading – from a stagnant condition, while the material is at rest,
to a transition to a granular flow, and back to a deposit profile.

The potential of the numerical method for the solution and optimization of industrial
granular flows problems is achieved by focusing on two specific industrial
applications in mining industry and pellet manufacturing: the silo discharge and the
calculation of the power draw in tumbling mills. Both examples are representative
when dealing with granular flows due to the presence of variations on the granular
material mechanical response.

Abstract

The paper is aimed to present industrial applications of sheet stamping simulation using new finite element formulations developed in the International Center for Numerical Methods in Engineering in Barcelona. Theoretical formulation is briefly reviewed. Both continuum and shell elements have been considered. The new shell elements developed are based on a geometrically exact shell model treating the shell as one-director Cosserat surface. The formulation of the continuum elements employs the multiplicative decomposition of the deformation gradient tensor into its elastic and plastic parts. The new finite element models have been implemented in the in-house explicit dynamic code STAMPACK. A number of practical problems of sheet metalforming have been solved with the program. Some of the problems, namely stamping of a kitchen sink, hydraulic forming of an aeronautical part and stamping of a food can, have been presented in the paper. The examples give an idea of practical information that can be obtained from the computer simulation of a forming process. The results confirm a good behaviour of the formulation and program used in the industrial applications.

Abstract

Abstract

Large plants in the process industry are monitored and maintained at regular intervals and repeatedly maintenance is either too early or too late. This causes unnecessary costs due to technicians, spare parts procurement as well as delivery issues and to high downtime costs due to unexpected shutdowns. In this context, the Remaining Useful Life (RUL) plays a major role, as it is an indicator of how long a machine or component can run without breakdown, repair or replacement. By predicting RUL using predictive maintenance, maintenance can be better planned, operational efficiency optimized, and unplanned downtime avoided. Optimizing the prediction accuracy should therefore always be in the foreground and is therefore the topic of this paper.

Abstract

Rotorcraft technologies pose great scientific and industrial challenges for numerical computing. As available computational resources approach the exascale, finer scales and therefore more accurate simulations of engineering test cases become accessible. However, shifting legacy workflows and optimizing parallel efficiency and scalability of existing software on new hardware is often demanding. This paper reports preliminary results in CFD and structural dynamics simulations using the T106A Low Pressure Turbine (LPT) blade geometry on Leonardo S.p.A.'s davinci-1 high-performance computing (HPC) facility. Time to solution and scalability are assessed for commercial packages Ansys Fluent, STAR-CCM+, and ABAQUS, and the open-source scientific computing framework PyFR. In direct numerical simulations of compressible fluid flow, normalized time to solution values obtained using PyFR are found to be up to 8 times smaller than those obtained using Fluent and STAR-CCM+. The findings extend to the incompressible case. All models offer weak and strong scaling in tests performed on up to 48 compute nodes, each with 4 Nvidia A100 GPUs. In linear elasticity simulations with ABAQUS, both the iterative solver and the direct solver provide speedup in preliminary scaling tests, with the iterative solver outperforming the direct solver in terms of time-to-solution and memory usage. The results provide a first indication of the potential of HPC architectures in scaling engineering applications towards certification by simulation, and the first step for the Company towards the use of cutting-edge HPC toolkits in the field of Rotorcraft technologies.