Online repository: https://speautomotive.com/acce-conference/2021-acce-papers-and-program-guides/ and also on: arXiv:2204.00909.
Abstract:
While welding of thermoplastic composites (TPCs) is a promising rivetless method to reduce weight, higher confidence in joints’ structural integrity and failure prediction must be achieved for widespread use in industry. In this work, we present an innovative study on damage detection for ultrasonically welded TPC joints with multi-walled carbon nanotubes (MWCNTs) and embedded buckypaper films. MWCNTs show promise for structural health monitoring (SHM) of composite joints, assembled by adhesive bonding or fusion bonding, through electrical resistance changes. This study focuses on investigating multifunctional films and their suitability for ultrasonic welding (USW) of TPCs, using two approaches: 1) MWCNT-filled polypropylene (PP) nanocomposites prepared via solvent dispersion, and 2) high conductivity MWCNT buckypaper embedded between PP films by hot pressing. Nanocomposite formulations containing 5 wt% and 10 wt% MWCNTs were synthesized using solvent dispersion method, followed by compression molding to manufacture films. The effect of MWCNT concentration on electrical and dynamic mechanical behavior of multifunctional films was examined with a Sourcemeter and Dynamic Mechanical Analyzer, and a comparison was made between 5 - 20 wt% MWCNT/PP films based on previous research. Glass fiber/polypropylene (GF/PP) composite joints were ultrasonically welded in a single lap shear configuration using buckypaper and MWCNT/PP films. Furthermore, electrical resistance measurements were carried out for joints under bending loads. It was observed that 15 wt% and 20 wt% MWCNT/PP films had higher stability and sensitivity for resistance response than embedded buckypaper and films with low MWCNT contents, demonstrating their suitability for USW and potential for SHM.
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Fastenerless Joining of Carbon Fiber Reinforced Thermoplastic Composite to Aluminum
Continuous efforts are underway for the reduction of the structural weight of transit through the introduction of a multi-material metal-composites system. There are major challenges in joining dissimilar materials to result in optimum structural integrity. The conventional joining techniques have limitations in terms of preparation time, weight penalty resulting from adhesives, and uncertainty in joint integrity. Recently adoption of macro scale mechanical interlocking in the adhesive joining resulted in significant improvement of joint performance. This made mechanical interlocking gain an attention for hybrid joining. In this study, fastenerless method of mechanical interlocking based on Japanese wood joining craft is considered for joining carbon fiber-reinforced polyamide thermoplastic composite to aluminum. Different interlocking joining designs (IJDs) were developed. The joints were obtained by force-fitting the male into the female counterpart. Here the male and female segments joined at macro level with no joining integrity at the interface. Further, these joints were tested and evaluated for tensile strength. A finite element analysis (FEA) model is developed for stress analysis and studying failure mechanisms of the IJDs. It was observed that the geometry of IJD dictates the failure mode and material composition governs the maximum strength achieved by a particular IJD. Each IJD showed higher load capacity with metal as a female counterpart to the composite compared to other way round.
more » « less- Award ID(s):
- 2052738
- PAR ID:
- 10513659
- Publisher / Repository:
- American Society of Mechanical Engineers
- Date Published:
- Journal Name:
- ASME 2023 International Mechanical Engineering Congress and Exposition
- ISBN:
- 978-0-7918-8760-8
- Format(s):
- Medium: X
- Location:
- New Orleans, Louisiana, USA
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1115/IMECE2023-116762
