Bending performance evaluation of aluminium alloy tubes filled with different cellular metal cores

Matej Vesenjak,Isabel Duarte,Joachim Baumeister,Hartmut Göhler,Lovre Krstulović-Opara,Zoran Ren

doi:10.1016/j.compstruct.2019.111748

Abstract

A comprehensive bending performance and energy absorption capability of aluminium alloy tubes filled with different cost-effective cellular metal cores were experimentally evaluated for the first time. The following cellular metal cores were evaluated: i) Advanced Pore Morphology (APM) foam, ii) hybrid APM foam and iii) Metallic Hollow Sphere Structures (MHSS). The results have been compared also with the performance of aluminium alloy tubes filled with (ex-situ and in-situ) closed-cell aluminium alloy foam. The three-point bending tests have been performed at two loading rates (quasi-static and dynamic) and supported by infrared thermography to evaluate the deformation mechanism, damage progress and failure modes. A thorough heat treatment sensitivity (due to the fabrication procedures of composite structures) study on the aluminium tubes has been performed as well. The results show that a reliable and predictable mechanical behaviour and failure can be achieved with proper combination of tubes and cellular metal core. A low scatter of bending properties and energy absorption capability has been observed. The hybrid APM and the ex-situ foam filled tubes achieved the highest peak load. However, they also exhibit a rapid load drop and abrupt failure once the structure has reached the peak load. The APM, MHSS and in-situ foam filled tubes show more ductile behaviour with a predictable failure mode.

Highlights

The increasing number of vehicles and the current global transport policies addressing the climate changes, have forced the transportation industry to substantially reduce greenhouse gas emissions in the new generation of vehicles [1]
Results demonstrate that the hybrid Advanced Pore Morphology (APM) foam filled tubes (~14.44 kN, quasi-static; ~15.07 kN, dynamic) and the ex-situ closed-cell foam filled tubes (~11.71 kN, quasi-static; ~17.39 kN, dynamic) achieved the highest values of the peak load in comparison to the APM foam filled tubes (~10.50 kN, quasi-static; ~10.65 kN, dynamic), Metallic Hollow Sphere Structure (MHSS) filled tubes (~10.89 kN, quasi-static; ~11.49 kN, dynamic) and in-situ foam filled tubes (~10.07 kN, quasi-static; ~10.19 kN, dynamic)
The MHSS filled tubes (Fig. 7) and the in-situ foam filled tubes [12] show a lower scatter of the properties in comparison to the APM foam filled tubes (Fig. 3), which might correspond to a stronger bonding combined with a mechanical interlocking between the filler and the inner tube wall resulting in a highly efficient load transfer from the tube to the filler

Summary

Introduction

The increasing number of vehicles and the current global transport policies addressing the climate changes, have forced the transportation industry to substantially reduce greenhouse gas emissions in the new generation of vehicles [1]. The manufacturers have found cost-effective solutions to fabricate safer vehicles To achieve these targets, the lightweight multi-material approach has proven to be very promising in terms of weight saving and preserving economic feasibility [3,4]. The lightweight multi-material approach has proven to be very promising in terms of weight saving and preserving economic feasibility [3,4] It allows the material selection for each part of a vehicle, based on several factors, such as mechanical performance, weight reduction, durability, manufacturability and costs. The use of such cellular materials does foster environmental advantages, and offers an approach to improve vehicle economics The latter is affected by increasing fuel costs and by reducing vehicle mass. Similar research has been carried out by using syntactic foams [15,16,17,18] as tube fillers [19]

Methods

Results

Conclusion