SMC/TPE bi‐layer configurations for structural vibration damping applications

Abstract

Sheet molding compounds (SMCs) have considerable potential as lightweight alternative to traditional materials used in automotive components. However, despite their outstanding mechanical properties, their vibration damping characteristics are often relatively poor for several applications. Therefore, enhancing the vibration damping capability of SMCs represents a field with increasing interest. Application of viscoelastic layers to high stiffness materials, such as SMCs, represents an effective approach to add vibration damping functionalities to lightweight structural components. In this work, the incorporation of thermoplastic elastomers (TPEs) is studied as a novel strategy to enhance the structural vibration damping capability of SMCs. Several types of SMC and TPEs have been considered and the effect of TPE‐SMC thickness ratio on the damping and stiffness properties is investigated. The viscoelastic properties and vibration damping performance were evaluated by dynamic mechanical analysis. The effect of TPE addition on stiffness was studied by three‐point bending. Results reveal the potential of the incorporation of thin TPE layers as cost‐effective strategy to enlarge the vibration damping efficiency of SMCs while maintaining their overall high stiffness. It is expected that the bi‐material configurations presented in the current study will contribute to advance the development of new lightweight multi‐functional solutions for modern transport applications.

Improvement of structural vibration damping performance of SMCs through SMC/TPE sandwich structures

“…Figures 2 and 3 illustrate the temperature dependency of the storage modulus ( E' ) and loss factor (tan δ ) of the single layer SMC and TPE samples, respectively, characterized in our previous publication 23 …”

“…The designation, material combination, and thickness definition of the produced plates is shown in Table 3. Besides, Table 4 defines the designation and details of the single layer epoxy and epoxy based FLD samples manufactured and experimentally characterized in our previous publication 23 …”

“…Besides, the viscoelastic layer is directly exposed to the environmental conditions of the structure. Even if the suitability of free‐layer damping structures for vibration damping applications has been demonstrated by combining SMC materials with thermoplastic elastomers (TPEs), 23 the direct exposure of the viscoelastic material to the environmental conditions may reduce their applicability in many cases 24…”

“…In a previous article, 23 the authors published a research where free‐layer damping structures were built by combining two commercially available TPEs, Versaflex VDT 5110‐50N and Versaflex VDT 5120‐40N, with two commercial SMC composites, an epoxy‐based carbon fiber SMC and an unsaturated polyester‐based glass fiber SMC, respectively, to study the enhancement on the vibration damping capabilities of the stiff material. The influence of the thickness of the viscoelastic layer on the final quasi‐static and damping properties of the structures was analyzed by means of quasi‐static three point bending tests (3 PB) and dynamic mechanical analysis (DMA).…”

“…Due to this, the current work has taken over from the previous publication to extend the research about the damping property improvement of SMCs by the generation of sandwich structures by the addition of TPEs. As the epoxy‐based free‐layer damping structures showed the most promising results in the previous work, 23 this study has been dedicated to analyzing the effects of sandwich structures for improving the damping properties of epoxy‐based SMCs. For that, bi‐material structures made of several TPE thicknesses have been examined by means of 3 PB and DMA in order to evaluate its effects on the strength, stiffness, damping properties of the structures, and temperature resistance.…”