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Communication Dans Un Congrès Année : 2023

Welding of high-performance thermoplastics and composites: from material properties to mechanical strength of assemblies

Christian Garnier
France Chabert

Résumé

The recent development of high-performance thermoplastics (TP) and related composites offers new possibilities for assembling of structures. Whatever the welding processes, they present an opportunity to reduce the impact of the entire life cycle of parts: fast cycle times, low energy consumption, no additional chemicals and the possibility of dismantling for recycling. In addition, welding can result in lighter and more durable parts compared to other joining techniques. Demanding applications such as aerospace, medical industry and others could benefit from higher reliability and repeatability of polymer welds. In this plenary lecture, we will focus on the family of polyaryletherketone matrix composites and three welding processes: induction welding (IW), transmission laser welding (TLW) and ultrasonic welding (USW). Joining two polymer substrates requires chemical compatibility and similar processing temperature ranges. Specific material properties are required depending on the welding process [1]. The physical mechanisms involved are related to softening and flow of the surface asperities to reach the intimate contact, diffusion of macromolecular chains, creation of entanglements and crystallization upon cooling. These mechanisms are linked to the process parameters: time, temperature, pressure. The prediction of the intimate contact Dic and the calculation of the healing degree Dh allow to define a bonding degree Db that is directly linked to the mechanical strength at the macroscopic scale, via the ratio of the critical energy restitution rate G1C of the assembly and those of the material substrates [2]. Different mechanical tests performed to assess the strength of the welds will be compared. Optimization of the process parameters will be discussed through thermal measurements at the interfaces [3]. The quality of the weld joint is assessed by a deep characterization of the weld and the heat-affected zone. Finally, a multi-physical numerical modelling of the USW process is presented as an example.
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Dates et versions

hal-04311589 , version 1 (28-11-2023)

Identifiants

  • HAL Id : hal-04311589 , version 1

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Christian Garnier, France Chabert, Arthur Lévy. Welding of high-performance thermoplastics and composites: from material properties to mechanical strength of assemblies. 3rd International conference on advanced joining processes, Oct 2023, Braga, Portugal. ⟨hal-04311589⟩
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