E15
V&V 2

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08:35
conference time (CEST, Berlin)
Modelling and Experimental Validation of Cable and Hose Dynamics
28/10/2021 08:35 conference time (CEST, Berlin)
Room: E
R. Faassen, B. Bukkems, D. Laro (MI-Partners, NLD)
R. Faassen, B. Bukkems, D. Laro (MI-Partners, NLD)
In the high-tech industry, the demands for performance tend to be stricter for each new generation of equipment. In order to obtain an acceptable position accuracy (often in the order of nanometres), a good isolation from the factory floor is desired. This is often realised by a compliant suspension of the machine, or at least, between the part of the machine that needs to be accurate and the outer world. Apart from this compliant suspension, often other links between the accurate machine part and the outer world exist. These can be links in the form of cables, hoses, and fibers. In order to ensure the required compliant coupling to the outer world, the compliance of these links should also be included in an early stage of the design process. Moreover, the dynamics of these links in the higher frequency ranges can also lead to undesired resonances. Therefore, accurate modelling is necessary for these kinds of links. In this study, finite element models have been generated for several kinds of links, such as hoses and cables. These links vary in shape (for example. L-shape or U shape), diameter, and material. In order to obtain accurate modelling results in all directions, the required stiffness matrix is evaluated between both clamped sides in 6 degrees of freedom. Using these models, the dynamic stiffness over a large frequency band has been simulated. Furthermore, experiments have been performed, in which the dynamic stiffness of such cables is measured. Using the experimental data, the models have been validated. The individual cable models can be used to model a cable assembly, where several cables in parallel are attached to a single connector on each side. These assemblies can then be used in a total machine model in order to analyse the dynamic behaviour of the complete system.
Dynamic stiffness, Craig-Bampton, Experiments, Dynamic link
08:55
conference time (CEST, Berlin)
Simulation Validation Through the Prism of Optical Measurements : Construction of a Validation Platform
28/10/2021 08:55 conference time (CEST, Berlin)
Room: E
F. Mathieu (EikoSim, FRA)
F. Mathieu (EikoSim, FRA)
In order to develop mechanical products faster and reduce development costs, industries rely more on and more on simulations, following the Model-Based Systems Engineering (MBSE) strategy. But to build more confidence in more refined simulation models, these models have to be backed up by a lot more real-world data, in order to avoid large design margins. Simulation validation today is often a long and energy-consuming part of CAE engineers’ job. Whether or not they follow closely ASME’s guide on verification and validation for solid mechanics, teams have to confront larger simulation models to larger amounts of test data. The goal is clear: proving higher-level simulation models have credibility will allow further removing tests from the development process, which in turn can radically reduce development time and costs. Optical measurement techniques like Digital Image Correlation (DIC) are currently used in test labs to increase the amount of test data and are viewed as a possibility to feed higher-level models. They indeed create a massive amount of test data, which is actually a new kind of problem when the current tools and methods are not fit to process these very large datasets. The problem is that current Finite Element (FE) simulation validation processes involve a substantial amount of pointwise simulation-to-test comparison, using the likes of Excel sheets or Python/Matlab scripts, for lack of capable solutions. In the context of DIC, this leads to engineers being forced to process virtual gauges instead of actually comparing displacements and strain fields and taking advantage of the large dataset. Optical methods, when used in conjunction with traditional sensors, are a way to drastically increase confidence in simulations. But they alone will not bridge the gap between simulation and testing. The bigger challenge is to connect all test data to simulation and SDM (Simulation Data Management) tools, in order to provide full access to all data in one place for fast decision-making. This paper’s goal is to propose an analysis of the situation CAE engineers currently meet, as well as a path to integrating all test data in the design thread, in the light of recent advances of optical measurement techniques. Recent development projects will be used as examples of how simulation validation and model calibration can benefit from a more systematic and extensive test data integration to the Finite Element models.
Validation, v&v, testing
09:15
conference time (CEST, Berlin)
On the Impact and Validation of Modelling Assumptions During the Virtual Design Process
28/10/2021 09:15 conference time (CEST, Berlin)
Room: E
A. Hardenberg (BTU Cottbus-Senftenberg, DEU); M. Fanter (Rolls-Royce Deutschland, DEU)
A. Hardenberg (BTU Cottbus-Senftenberg, DEU); M. Fanter (Rolls-Royce Deutschland, DEU)
The use of virtual prototypes and the simulation-driven design have become vital factors in lowering costs and reducing the time-to-market while developing increasingly complex products like aeroengines. To simulate the structural behaviour of a design, the relevant physics of the real-world problem must be abstracted and idealized to form a mathematical description of the physics of the system. While there exist standardized procedures to verify the numerical representation of the computational model, the validation of the different modelling assumptions remains a major challenge. Since experimental data is limited during the virtual design process, the validation of the modelling assumptions often cannot be supported by a physical test. The NAFEMS Engineering Simulation Quality Management Standard (ESQMS) recognizes two methods for validation not supported by physical test: the comparison of simulation results with those from alternative mathematical models and the review by subject matter experts. In this paper the method of comparing models of different fidelity is adapted and applied to a turbine casing assembly of an aeroengine, consisting of a high-pressure turbine casing (HPTC), a low-pressure turbine casing (LPTC), an exhaust outlet guide vane (EOGV) and a rear bearing support structure (RBSS). For subsequent detailed analysis of the various engine components, the accuracy of the calculated interface forces needs to be ensured. To showcase the influence of different modelling assumptions on the simulation prediction, the models are correlated to a high-fidelity representation of the casing structure. Since the interface forces differ depending on the loading conditions, the difference in the stiffness and mass properties of the modelled structures are first evaluated by correlating the results of the corresponding free-free modal analyses. Static analyses and correlation of the models subject to a bearing load is performed to assess and compare the impact on the load share and load distribution caused by the modelling changes. Different methods are demonstrated which help to quantify the effect of the different assumptions.
09:35
conference time (CEST, Berlin)
Plastic Properties of Sleeve/Tape Reinforced Electric Multi-Wire Harnesses
28/10/2021 09:35 conference time (CEST, Berlin)
Room: E
C. Diaconu (Siemens Digital Industries Software, JPN); P. Andry (Siemens Digital Industries Software, BEL);
C. Diaconu (Siemens Digital Industries Software, JPN); P. Andry (Siemens Digital Industries Software, BEL);
Recent increase in development of complex electro-mechanical systems has resulted in an increased usage of electric cables harnessed and confined in enclosed spaces and often operating at high temperatures and/or within powerful electromagnetic fields. Generating digital twins of electric cables and wire harness systems is a multidisciplinary task consisting in designing both the electrical system circuit and the mechanical three-dimensional layout. The mechanical design of the three-dimensional layout is challenging because the non-linear behavior of many electric cables and wire harnesses enclosed within confined spaces must be considered for validating the results. This study deals with determining the non-linear mechanical properties of wire harnesses that are enclosed in tubular sleeves and/or reinforced with tapes. Such properties are essential data necessary for validating and optimizing the digital twins of the electric cables and wire harness assemblies. These mechanical properties are determined by data fitting wire harness CAE models against test data of multiple wire harnesses with given numbers of wires and enclosed in various sleeves and/or tapes. The dependency of the wire harness mechanical properties on parameters such as the number of wires, harness diameter and sleeve and/or tape type is observed and analyzed. The results show that both linear and non-linear mechanical properties of the wire harnesses depend on these parameters. The dependency functions of the wire harnesses mechanical properties on the number of wires is particularly important since this number can change significantly within a wire harness assembly. Fortunately, these functions exhibit smooth dependency on the wire harness diameter, and indirectly on the number of wires. Therefore, interpolation can be used successfully to determine from a limited set of test data the mechanical properties of harnesses with varying number of wires. Such interpolated parameters were later used to determine shapes and reaction forces on a wire harness design assembly. The results have shown significant harness shapes and reaction force differences when compared against a model that does not consider the permanent deformations in wires.
Electric Cables, Wire Harnesses, Nonlinear Materials, Geometrical Non-linearities, Plasticity, Mechanical Properties, Digital Twin
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