Determining the damping behavior of fiber reinforced composites

For metal–plastic composites with thin shear-sensitive cores, high damping can be determined. These materials were developed to reduce the structure-borne noise and are therefore used for thin-walled components with bending loads. In addition to the known sensitivity due to the temperature and frequency, these materials show a significant dependency on vibration amplitudes. Within the framework of this study, the nonlinear damping of metal–plastic composites was determined experimentally using free-vibrating cantilever beams. A detailed analysis of the derived velocity–time curves showed a nonlinear damping within the decay. An exponential approach was successfully used to describe the relation between damping and current deflection. Furthermore, a strain energy-based evaluation is introduced to quantify the share of the core contributions. For this purpose, the strain energy of several acoustically sensitive car components as well as the beams with varying supports and vibration lengths were determined numerically with a finite element analysis. The strain energy ratio of the cores was then derived as a comparative measurement and within a finite element-based design of experiments. A cantilever beam setup with a component-specific beam length representing similar core strain energy ratios was retested and showed a similar exponential amplitude dependence but higher damping parameters.

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“…Therefore, the experimental determination and numerical modeling of frequency and temperature effects has been under extensive investigation. 3–6…”

Section: Introductionmentioning

confidence: 99%

Metal–plastic composites with amplitude-dependent constraint layer damping

Klaerner

Wuehrl

Kroll

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…stiffness and damping) (Klaerner et al, 2012). Sensitive parameters are fibre volume content, fibre orientation as well as stacking sequence resulting in non-linear dependencies (Ulke-Winter et al, 2013). Either genetic or gradient based optimisations require numerous finite-element simulations.…”

Section: Introductionmentioning

confidence: 99%

Simulative measures for structure borne sound radiation of composites

Klaerner

Marburg

Kroll

2013

The Journal of the Acoustical Society of America

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Due to the high stiffness-to-weight ratio, composite structures tend to be acoustic sensitive. The sound emission of such radiating components is commonly measured by the sound power requiring the determination of the sound intensity in normal direction and—in numerical simulations—the sound pressure on the radiating surface. Assuming a unit radiation efficiency all-over the surface and neglecting local effects, the equivalent radiated power (ERP) is a common approach for an upper bound of structure borne noise. Therein, the sound power finally results from the squared velocity integrated over the radiating surface and the fluid impedance. As ERP usually requires extra post processing to consider the velocity in normal surface direction, the kinetic energy is essential in common FEA results including all velocity components apart from the normal direction, too. Moreover, ERP necessitates the knowledge of the radiating surfaces increasing the effort especially for complex geometries. Thus, the possibilities and limits of estimating the emitted sound power by the kinetic energy as well as using the ERP method will be shown. Test cases are a rectangular plate and a thin-walled bonded part with linear anisotropic material properties.

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Hybride Bauweisen und Technologien

Kroll

2019

Technologiefusion Für Multifunktionale Leichtbaustrukturen

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Determining the damping behavior of fiber reinforced composites

Cited by 13 publications

References 14 publications

Metal–plastic composites with amplitude-dependent constraint layer damping

Metal–plastic composites with amplitude-dependent constraint layer damping

Simulative measures for structure borne sound radiation of composites

Hybride Bauweisen und Technologien

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