Fundamentals of Force-Controlled Friction Riveting: Part II-Joint Global Mechanical Performance and Energy Efficiency.

Gonçalo Pina Cipriano,Sergio Amancio-Filho,Jorge Dos Santos,Lucian Blaga,Pedro Vilaça

doi:10.3390/ma11122489

Gonçalo Pina Cipriano, Sergio Amancio-Filho + Show 3 more

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https://doi.org/10.3390/ma11122489

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Abstract

The present work investigates the correlation between energy efficiency and global mechanical performance of hybrid aluminum alloy AA2024 (polyetherimide joints), produced by force-controlled friction riveting. The combinations of parameters followed a central composite design of experiments. Joint formation was correlated with mechanical performance via a volumetric ratio (0.28–0.66 a.u.), with a proposed improvement yielding higher accuracy. Global mechanical performance and ultimate tensile force varied considerably across the range of parameters (1096–9668 N). An energy efficiency threshold was established at 90 J, until which, energy input displayed good linear correlations with volumetric ratio and mechanical performance (R-sq of 0.87 and 0.86, respectively). Additional energy did not significantly contribute toward increasing mechanical performance. Friction parameters (i.e., force and time) displayed the most significant contributions to mechanical performance (32.0% and 21.4%, respectively), given their effects on heat development. For the investigated ranges, forging parameters did not have a significant contribution. A correlation between friction parameters was established to maximize mechanical response while minimizing energy usage. The knowledge from Parts I and II of this investigation allows the production of friction riveted connections in an energy efficient manner and control optimization approach, introduced for the first time in friction riveting.

Highlights

A current concern in industry is the compromise between the benefits of using lightweight materials and how to integrate these into larger multi-material designs
Given existing limitations related to the use of more conventional methods to perform connections and the need to further push the boundaries on new design solutions and methodologies, several alternative joining technologies have been recently developed
The materials used in the present work were polyetherimide (PEI) and AA2024-T351

Summary

Introduction

A current concern in industry is the compromise between the benefits of using lightweight materials and how to integrate these into larger multi-material designs. The wider the range of possible joining technologies to perform hybrid connections, the less compromising or restricted the usage of these materials might be. The more traditional and well-established methods to perform connections between different material classes are mechanical fastening [1] and adhesive bonding [2]. Given existing limitations related to the use of more conventional methods to perform connections (referred to in Part I of this work [3] and in References [2,4,5]) and the need to further push the boundaries on new design solutions and methodologies, several alternative joining technologies have been recently developed. Abibe et al [4] investigated the mechanical behavior of hybrid staked joints, performed using aluminum alloy AA2024-T351 and a

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