Material Models and Parameterization for Cable Simulation

New Approaches for Modeling Flexible Structures

In special applications, it may be necessary to consider more complex effects, as cables and hoses can also behave nonlinearly and inelastically in reality. We are therefore continuously working on new approaches for constitutive modeling for flexible slender structures. These include, for example:

• Permanent plastic deformations
• Nonlinear behavior and coupled load cases in 3D
• Cable parameterization for operational simulations

We develop corresponding cable tests based on classical beam experiments from experimental mechanics to investigate complex behavior.

Efficient Estimation of Model Parameters in Early Design Phases

In automotive applications, cables are rarely installed individually, but are mostly bundled in the wiring harness. Due to the wide variety of equipment options in passenger cars, the possible combinations are almost endless, but they determine the mechanical behavior of the cable bundle. With our Bundle Properties Estimator (BPE), the parameters of such bundles can be estimated early on in the development phase – even without hardware prototypes. The tool complements IPS Cable Simulation and requires only a few, easily determined input data.

Permanent Plastic Deformation

Cables usually do not behave elastically under large deformations. Most people are familiar with this phenomenon from everyday life, where cables often develop permanent kinks. In the automotive sector, these effects become relevant when cables are for example bent significantly  during assembly or repeatedly during operation. We therefore investigate the behavior of cables and hoses under large deformations in experiments and develop inelastic cable models that can, for example, represent plastic behavior in the form of hysteresis. Hysteresis describes how the reaction of the cable depends not only on its current state, but also on its load history.

Nonlinear Behavior and Coupled Load Cases in 3D

We investigate how cables respond to large bending and torsional deformations in three-dimensional space that lead to nonlinear behavior. We also consider the coupling of different load cases to understand how pre-deformations caused by torsion influence the bending behavior. These effects are crucial for simulations in which the accuracy of forces and moments, for example on fasteners, plays a central role.

more about »Interaction of Cables With Flexible Clips and Holders«

Cable Parameterization for Operational Simulation

Cables are often exposed to vibrations during operation. That is why we investigate time-dependent material effects such as damping and viscoelasticity. We simulate the vibrations of cables for installation space design, calculate the loads on fastenings, and analyze noise and vibration transmission in NVH investigations. NVH stands for Noise, Vibration, and Harshness.

more about »Vibration Dynamics and NVH for Cables and Hoses«

Cable Experiments to Investigate Complex Effects

The observation of phenomena in suitable experiments forms the basis of constitutive modeling. We therefore develop tests that are specifically well-suited for the investigation of cables and hoses under realistic loads and go beyond standard tests in experimental beam mechanics. Research prototypes of our MeSOMICS^® measuring machine enable us, for example, to investigate the bending of cables in the nonlinear range.

In addition, we use a test rig in which a robot arm deforms cables in space. This allows us to generate various boundary conditions, including coupled deformations, and measure the resulting loads. A camera documents the deformations, and the coupling with IPS Cable Simulation allows direct comparison of real and simulated samples.