108
7 Virtual testing approach for sandwich panel joints
on virtual tests. Therefore, this typically involves drastic changes in the geometry of the
joint. Lastly, in case the virtual test is intended to predict uncertainties, the corresponding requirements for the probabilistic analysis need to be defined in Phase 1 as well.
Therefore, the three main aspects that should be addressed by the requirement definition are as follows
Degree of damage modelling
Computational effort
Uncertainty (not covered in this work).
With regards to the demonstration example, the intended application is the evaluation
of the effect of different constituents (face sheet, honeycomb core, adhesives and inserts) on the pull-out strength. Therefore, only a limited number of design alternatives
are to be studied. At the same time, the model should be able to predict the point of
catastrophic failure. A computational time in the range of about 2 h to 4 h per simulation
is targeted. This allows to perform a full parameter study containing several simulations
runs over night. The model is supposed to run on a state-of-the-art Intel i7 workstation.
No uncertainty analysis is considered.
Identification of relevant mechanical effects
In the second part of the problem analysis phase the governing mechanical effects are
identified based on available results and documentation of the reference test. These effects generally correspond to the damage mechanisms, which contribute to the overall
failure behavior. The required test documentation generally includes the force-displacement or stress-strain relationship, which characterizes the mechanical response and
damage progression of the specimen. In addition, live examination results such as video
recording as well as pre- and post-test analysis of the specimens are required. The exact
set of required test documentation and analyses depends on the investigated specimen
and the evident damage mechanisms. Common analysis methods are introduced in section 7.4, where the process of structural tests and analysis methods as part of the model
development phase is described. Once the mechanical effects and damages are identified, they are mapped onto the test progression in order to ensure that the sequence of
the effects is understood. This can be done by sub-dividing the force displacement curve
into stages and assigning the different effects to these stages. Depending on the required
degree of damage modelling, the relevant mechanical effects are lastly established.
Phase 1 concludes with a list of relevant mechanical effects, which have to be implemented in order to represent the failure behavior observed in the reference test.
In case of the demonstration example, the reference test was observed simultaneously
from the top and the bottom by two cameras with 120 fps. This ensures that the behavior of both faces is captured throughout the test. Since the damage progression in the
7 Virtual testing approach for sandwich panel joints
on virtual tests. Therefore, this typically involves drastic changes in the geometry of the
joint. Lastly, in case the virtual test is intended to predict uncertainties, the corresponding requirements for the probabilistic analysis need to be defined in Phase 1 as well.
Therefore, the three main aspects that should be addressed by the requirement definition are as follows
Degree of damage modelling
Computational effort
Uncertainty (not covered in this work).
With regards to the demonstration example, the intended application is the evaluation
of the effect of different constituents (face sheet, honeycomb core, adhesives and inserts) on the pull-out strength. Therefore, only a limited number of design alternatives
are to be studied. At the same time, the model should be able to predict the point of
catastrophic failure. A computational time in the range of about 2 h to 4 h per simulation
is targeted. This allows to perform a full parameter study containing several simulations
runs over night. The model is supposed to run on a state-of-the-art Intel i7 workstation.
No uncertainty analysis is considered.
Identification of relevant mechanical effects
In the second part of the problem analysis phase the governing mechanical effects are
identified based on available results and documentation of the reference test. These effects generally correspond to the damage mechanisms, which contribute to the overall
failure behavior. The required test documentation generally includes the force-displacement or stress-strain relationship, which characterizes the mechanical response and
damage progression of the specimen. In addition, live examination results such as video
recording as well as pre- and post-test analysis of the specimens are required. The exact
set of required test documentation and analyses depends on the investigated specimen
and the evident damage mechanisms. Common analysis methods are introduced in section 7.4, where the process of structural tests and analysis methods as part of the model
development phase is described. Once the mechanical effects and damages are identified, they are mapped onto the test progression in order to ensure that the sequence of
the effects is understood. This can be done by sub-dividing the force displacement curve
into stages and assigning the different effects to these stages. Depending on the required
degree of damage modelling, the relevant mechanical effects are lastly established.
Phase 1 concludes with a list of relevant mechanical effects, which have to be implemented in order to represent the failure behavior observed in the reference test.
In case of the demonstration example, the reference test was observed simultaneously
from the top and the bottom by two cameras with 120 fps. This ensures that the behavior of both faces is captured throughout the test. Since the damage progression in the