Selective mass scaling and critical time-step estimate for explicit dynamics analyses with solid-shell elements

Cocchetti, Giuseppe; Pagani, M.; Perego, U.

doi:10.1016/j.compstruc.2012.10.021

Cited by 62 publications

(79 citation statements)

References 26 publications

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“…The method is a natural extension to multi-layer structures of what has been proposed in Cocchetti et al (2013); Pagani et al (2014); Cocchetti et al (2015) for homogeneous, onelayer shells. The scaling procedure can be applied to distorted 8-node solid-shell elements, with nodal displacements dofs.…”

Section: Discussionmentioning

confidence: 99%

“…When a single-layer problem is addressed, the selective mass scaling technique proposed in Cocchetti et al (2013Cocchetti et al ( , 2015 has been shown to preserve the diagonal structure not only of a single element mass matrix, but also of the assembled structure, when its motion is described as in (19) in terms of transformed dofs. This implies that transformed element mass contributions in (18), coming from adjacent elements sharing the same global dofs, have to be assembled.…”

Section: Introductionmentioning

confidence: 99%

“…A possible solution to this problem has been proposed in Tkachuk and Bischoff (2015), where a method for a direct variational construction of a sparse inverse matrix has been formulated, together with a new selective mass scaling to be applied directly to the inverse mass matrix. A different approach has been considered in Olovsson et al (2004) and Cocchetti et al (2013), where the relative motion in the thickness direction of thin-walled structures has been penalized by the addition of artificial inertia. The method proposed in Cocchetti et al (2013), specifically conceived for parallelepiped solid-shell elements, has been extended to distorted solid-shell elements in Cocchetti et al (2015), together with a strategy for the computation of the optimal scaling factor and of the critical time step size.…”

Section: Introductionmentioning

confidence: 99%

“…Following Cocchetti et al (2013Cocchetti et al ( , 2015, the element geometry and kinematics are expressed in terms of variables related to middle surface nodes, as in classical shell elements, and to the element corner fibers, i.e. to the segments connecting corresponding pairs of nodes belonging to the lower and upper surfaces (Fig.…”

Section: Introductionmentioning

confidence: 99%

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8-Node solid-shell elements selective mass scaling for explicit dynamic analysis of layered thin-walled structures

2015

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To overcome the issue of spurious maximum eigenfrequencies leading to small steps in explicit time integration, a recently proposed selective mass scaling technique, specifically conceived for 8-node hexahedral solid-shell elements, is reconsidered for application to layered shells, where several solid-shell elements are used through the thickness of thin-walled structures.In this case, the resulting scaled mass matrix is not perfectly diagonal. However, the introduced coupling is shown to be limited to the nodes belonging to the same fiber through the thickness, so that the additional computational burden is almost negligible and by far compensated by the larger size of the critical time step. The proposed numerical tests show that the adopted mass scaling leads to a critical time step size which is determined by the element in-plane dimensions only, independent of the layers number, with negligible accuracy loss, both in small and large displacement problems.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

8-Node solid-shell elements selective mass scaling for explicit dynamic analysis of layered thin-walled structures

2015

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“…In combination with an iterative solver for acceleration (see [9]) it proved to be efficient for some applications such as deep drawing of metal sheets and drop tests [3], dynamics of solid-shell modeled structures [4].…”

Section: Introductionmentioning

confidence: 99%

Applications of Variationally Consistent Selective Mass Scaling in Explicit Dynamics

Tkachuk¹,

Bischoff²

2014

Proceedings of the 4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Abstract. The aim of Selective Mass Scaling (SMS) in context of non-linear structural mechanics is to increase the critical time-step for explicit time integration without substantial loss in accuracy in the lower modes. The Conventional Mass Scaling (CMS) adds artificial mass only to diagonal terms of the lumped mass matrix and thus preserves diagonal format of mass matrix. It is usually applied in little number of small or stiff elements, like spot-welds in car crash, whose high eigenfrequencies limit time-step. However, translational and rotational inertia of the structure increases, which may cause non-physical phenomena. SMS technique adds artificial terms both to diagonal and non-diagonal terms, which results in non-diagonal mass matrix, but at least allows preservation of translational mass. Thus SMS can be used uniformly in domain with less non-physical artifacts. The previous works on SMS rely on algebraically constructed mass scaling matrices or stiffness proportional mass scaling. These approaches provide very small choice of mass scaling templates and they lack rigorous variational formulation. The goal of this paper is to develop variational basis for SMS with consistent discretization of inertial term and to assess efficiency of the proposed approach.

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A fast weakly intrusive multiscale method in explicit dynamics

Bettinotti

Allix

Perego

et al. 2014

Int. J. Numer. Meth. Engng

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SUMMARYThis paper presents new developments on a weakly-intrusive approach for the simplified implementation of space and time multiscale methods within an explicit dynamics software. The "substitution" method proposed in previous works allows to take advantage of a global coarse model, typically used in an industrial context, running separate, refined in space and in time, local analyses only where needed. The proposed technique is iterative, but the explicit character of the method allows to perform the global computation only once per global time step, while a repeated solution is required for the small local problems only. Nevertheless, a desirable goal is to reach convergence with a reduced number of iterations. To this purpose, we propose here a new iterative algorithm based on an improved interface inertia operator. The new operator exploits a combined property of velocity Hermite time interpolation on the interface and of the central difference integration scheme, allowing the consistent upscaling of interface inertia contributions from the lower scale. This property is exploited to construct an improved mass matrix operator for the interface coupling, allowing to significantly enhance the convergence rate. The efficiency and robustness of the procedure is demonstrated through several examples of growing complexity.

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Selective mass scaling and critical time-step estimate for explicit dynamics analyses with solid-shell elements

Cited by 62 publications

References 26 publications

8-Node solid-shell elements selective mass scaling for explicit dynamic analysis of layered thin-walled structures

8-Node solid-shell elements selective mass scaling for explicit dynamic analysis of layered thin-walled structures

Applications of Variationally Consistent Selective Mass Scaling in Explicit Dynamics

A fast weakly intrusive multiscale method in explicit dynamics

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