Optimization of Mechanical Properties and Damage Tolerance in Polymer-Mineral Multilayer Composites

Abstract

Talcum reinforced polypropylene was enhanced with a soft type of polypropylene in order to increase the impact strength and damage tolerance of the material. The soft phase was incorporated in the form of continuous interlayers, where the numbers of layers ranged from 64 to 2048. A blend with the same material composition (based on wt% of the used materials) and the pure matrix material were investigated for comparison. A plateau in impact strength was reached by layered architectures, where the matrix layer thickness was as small or smaller than the largest talcum particles. The most promising layered architecture, namely, 512 layers, was subsequently investigated more thoroughly using instrumented Charpy experiments and tensile testing. In these tests, normalised parameters for stiffness and strength were obtained in addition to the impact strength. The multilayered material showed remarkable impact strength, fracture energy and damage tolerance. However, stiffness and strength were reduced due to the addition of the soft phase. It could be shown that specimens under bending loads are very compliant due to a stress-decoupling effect between layers that specifically reduces bending stiffness. This drawback could be avoided under tensile loading, while the increase in toughness remained high.

A Novel Implementation of the LDEM in the Ansys LS-DYNA Finite Element Code

“…Some observations can be made on Equation (13). When ε p is equal to ε u , the minimum area of bilinear constitutive law is obtained, as ε u has to be larger or equal to ε p in order to ensure the energy equilibrium into the element.…”

“…As far as layered materials are concerned, several layers made of different materials are stacked, and may be characterised by different orientations and thickness [10][11][12][13]. Each layer or group of layers is devoted to a specific task, ranging from structural strength to insulation or lightening.…”

Multimaterial Extrusion‐Based Additive Manufacturing of Compliant Crack Arrester: Influence of Interlayer Length, Thickness, and Applied Strain Rate

“…[6,7,18] Among other mechanisms, the underlying phenomenon providing these improved behaviors can be explained by the material inhomogeneity effect, which has been studied intensively. [6,[20][21][22][23][24][25] This effect is caused by the spatial variation of mechanical properties (i.e., Young´s modulus and yield strength). [6,26,27] A crack propagating through the material is arrested inside a soft layer and further spreading is hindered or prevented.…”

Delamination effect on the mechanical behavior of 3D printed polymers

“…Nevertheless, other barely studied aspects such as the delamination of ADM polymers, deep analysis of rupture mechanisms, and damage modeling of 3D printed ABS polymers. The delamination effect is widely studied in composites and multilayer materials [5]. This phenomenon is recognized as a principal matter for composites, and much research has tried to deal with composites' heterogeneity and the study of the interactions between layers [6].…”