Static Mechanical Properties of Expanded Polypropylene Crushable Foam.
Przemysław Rumianek1, Tomasz Dobosz2, Radosław Nowak1
1Faculty of Automotive and Construction Machinery Engineering, Warsaw University of Technology, 02-524 Warsaw, Poland.
Materials (Basel, Switzerland)
|January 9, 2021
Summary
This study shows that higher strain rates and density increase expanded polypropylene (EPP) foam
Area of Science:
- Materials Science
- Polymer Engineering
- Mechanical Engineering
Background:
- Closed-cell expanded polypropylene (EPP) foam is vital for energy absorption in automotive safety components like bumpers.
- Understanding EPP foam's mechanical behavior under dynamic loading is crucial for effective protective structure design.
Purpose of the Study:
- To investigate how loading strain rate, material density, and microstructure affect the compressive strength and energy absorption of EPP foams.
- To provide data for optimizing EPP foam selection in dynamic impact applications.
Main Methods:
- Performed quasi-static compressive strength tests at strain rates from 0.2 to 25 mm/s.
- Tested EPP foams with densities ranging from 20 to 220 g/dm³.
- Utilized numerical simulations with ABAQUS software and verified with experimental finite element method tests.
Main Results:
- Increased strain rate and foam density significantly enhanced compressive strength and energy absorption.
- Higher temperatures (ambient and sample) led to decreased compressive strength and energy absorption.
- Variations in foam microstructure influenced strength and energy absorption even at identical densities and strain rates.
Conclusions:
- EPP foam's mechanical properties are highly sensitive to strain rate, density, and temperature.
- Microstructure tailoring offers a pathway to achieve specific material properties for diverse applications.
- Precise material characterization is key to expanding the use of EPP foams in demanding applications.
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