Global Animation Theory offers detailed and diverse insights into the methodologies of contemporary animation studies, as well as the topics relevant for today’s study of animation. The contact ...between practical and theoretical approaches to animation at Animafest Scanner, is closely connected to host of this event, the World Festival of Animated Film Animafest Zagreb. It has given way to academic writing that is very open to practical aspects of animation, with several contributors being established not only as animation scholars, but also as artists. This anthology presents, alongside an introduction by the editors and a preface by well known animation scholar Giannalberto Bendazzi, 15 selected essays from the first three Animafest Scanner editions. They explore various significant aspects of animation studies, some of them still unknown to the English speaking communities.
(...) Since then, the academic world has undergone some radical changes, and the process is not near its conclusion. Academia is a very close-knit environment, proud of its conditions and ...requirements, methods, and procedures. Still, the impact of the Covid-19 pandemic is providing unexpected possibilities to develop, question and reform central elements of it.
Classical geometrically exact Kirchhoff and Cosserat models are used to study the nonlinear deformation of rods. Extension, bending and torsion of the rod may be represented by the Kirchhoff model. ...The Cosserat model additionally takes into account shearing effects. Second order finite differences on a staggered grid define discrete viscoelastic versions of these classical models. Since the rotations are parametrised by unit quaternions, the space discretisation results in differential-algebraic equations that are solved numerically by standard techniques like index reduction and projection methods. Using absolute coordinates, the mass and constraint matrices are sparse and this sparsity may be exploited to speed-up time integration. Further improvements are possible in the Cosserat model, because the constraints are just the normalisation conditions for unit quaternions such that the null space of the constraint matrix can be given analytically. The results of the theoretical investigations are illustrated by numerical tests.
In this paper, we present a viscoelastic rod model that is suitable for fast and accurate dynamic simulations. It is based on Cosserat’s geometrically exact theory of rods and is able to represent
...extension
,
shearing
(‘stiff’ dof),
bending
and
torsion
(‘soft’ dof). For inner dissipation, a consistent damping potential proposed by Antman is chosen. We parametrise the rotational dof by unit quaternions and directly use the quaternionic evolution differential equation for the discretisation of the Cosserat rod curvature.
The discrete version of our rod model is obtained via a finite difference discretisation on a staggered grid. After an index reduction from three to zero, the right-hand side function
f
and the Jacobian
∂
f
/
∂
(
q
,
v
,
t
) of the dynamical system
,
is free of higher algebraic (e.g. root) or transcendental (e.g. trigonometric or exponential) functions and, therefore, cheap to evaluate. A comparison with
Abaqus
finite element results demonstrates the correct mechanical behaviour of our discrete rod model. For the time integration of the system, we use well established stiff solvers like
Radau5
or
Daspk
. As our model yields computational times within milliseconds, it is suitable for interactive applications in ‘virtual reality’ as well as for multi-body dynamics simulation.
This paper describes the numerical investigation of the mechanical behaviour of a structural component of an aircraft wing flap support impacted by a wheel rim fragment. The support link made of ...composite materials was modelled in the commercial finite element code Abaqus/Explicit, incorporating intralaminar and interlaminar failure modes by adequate material models and cohesive interfaces. Validation studies were performed step by step using quasi-static tensile test data and low velocity impact test data. Finally, high velocity impact simulations with a metallic rim fragment were performed for several load cases involving different impact angles, impactor rotation and pre-stress. The numerical rim release analysis turned out to be an efficient approach in the development process of such composite structures and for the identification of structural damage and worst case impact loading scenarios.
A numerical study on the structural mechanics of bonded composite structures, which were interlaminary reinforced by metallic sheet and pin elements, is presented in this paper. For the investigation ...of the potential of this reinforcing technology, finite element models on meso and macro scale were studied, which were successfully validated against experimental test results. On the example of quasi-statically loaded single-lap shear test specimens, the macro scale model was used to implement different configurations of the reinforcements including variations of the pin geometry as well as their arrangements. Passing a variable search according to Shainin, the influences of various design factors on the structural performance of the reinforced joints were evaluated. In addition, the main effects were identified as the pin and sheet thickness among others concerning the applicable load as well as the elongation of the joint. Furthermore, the analyzes of the interdependencies showed, that the majority of the variables weakens the effects of the other ones.
A testing method is presented to determine the pull-out behavior of interleaving metallic z-reinforcements for carbon fiber reinforced polymer (CFRP) laminates and joints. Energy absorbing mechanisms ...are described with respect to the metallic materials and means of surface pretreatment applied. Mechanical, wet-chemical and physical pretreatments result in milli-, micro- and nanoscaled oxide morphologies of titanium and stainless steel surfaces. Both, a high macro roughness of the reinforcement surface and a low difference in thermal expansion with regard to the surrounding CFRP is clearly proven to feature the highest level of energy absorption during pull-out tests. Surface analyses through scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) indicate laser-induced nanostructure’s scale and morphology to provide good adhesion properties but not to allow macroscopic friction between metal surface and epoxy resin.
We present a generalisation of existing Lipschitz estimates for the stop and play operator for an arbitrary convex and closed characteristic, which contains the origin, in a separable Hilbert space. ...We are especially concerned with the dependence of stop and play on different scalar products.
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