On the Constitutive Response Characterization for Composite Materials via Data-Driven Design Optimization

2011 ◽  
Author(s):  
John G. Michopoulos ◽  
John G. Hermanson ◽  
Athanasios Iliopoulos ◽  
Samuel Lambrakos ◽  
Tomonari Furukawa
Keyword(s):  
Composite Materials ◽  
Design Optimization ◽  
Strain Energy ◽  
Polymer Matrix Composites ◽  
Large Strain ◽  
Surface Strain ◽  
Matrix Composites ◽  
Constitutive Response ◽  
The Difference

In the present paper we focus on demonstrating the use of design optimization for the constitutive characterization of anisotropic material systems such as polymer matrix composites, with or without damage. All approaches are based on the availability of experimental data originating from mechatronic material testing systems that can expose specimens to multidimensional loading paths and can automate the acquisition of data representing the excitation and response behavior of the specimens involved. Material characterization is achieved by minimizing the difference between experimentally measured and analytically computed system responses as described by strain fields and surface strain energy densities. A one dimensional model is presented first to elucidate the design optimization for the general non-linear constitutive response. Small and large strain formulations based on strain energy density decompositions are developed and utilized for determining the constitutive behavior of composite materials. Examples based on both synthetic and actual data demonstrate the successful application of design optimization for constitutive characterization.

Data-Driven Design Optimization for Composite Material Characterization

2011 ◽  
Vol 11 (2) ◽  
Author(s):  
John G. Michopoulos ◽  
John C. Hermanson ◽  
Athanasios Iliopoulos ◽  
Samuel G. Lambrakos ◽  
Tomonari Furukawa
Keyword(s):  
Energy Density ◽  
Design Optimization ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Polymer Matrix Composites ◽  
Large Strain ◽  
Surface Strain ◽  
Structural Shape ◽  
Material Systems ◽  
The Difference

The main goal of the present paper is to demonstrate the value of design optimization beyond its use for structural shape determination in the realm of the constitutive characterization of anisotropic material systems such as polymer matrix composites with or without damage. The approaches discussed are based on the availability of massive experimental data representing the excitation and response behavior of specimens tested by automated mechatronic material testing systems capable of applying multiaxial loading. Material constitutive characterization is achieved by minimizing the difference between experimentally measured and analytically computed system responses as described by surface strain and strain energy density fields. Small and large strain formulations based on additive strain energy density decompositions are introduced and utilized for constructing the necessary objective functions and their subsequent minimization. Numerical examples based on both synthetic (for one-dimensional systems) and actual data (for realistic 3D material systems) demonstrate the successful application of design optimization for constitutive characterization.

scholarly journals Antibacterial Composite Materials Based on the Combination of Polyhydroxyalkanoates With Selenium and Strontium Co-substituted Hydroxyapatite for Bone Regeneration

2021 ◽  
Vol 9 ◽  
Author(s):  
Elena Marcello ◽  
Muhammad Maqbool ◽  
Rinat Nigmatullin ◽  
Mark Cresswell ◽  
Philip R. Jackson ◽  
...  
Keyword(s):  
Composite Materials ◽  
Polymer Matrix Composites ◽  
Antibacterial Properties ◽  
Bacterial Cells ◽  
Matrix Composites ◽  
E Coli ◽  
Regeneration Of Bone Tissue ◽  
High Reduction

Due to the threat posed by the rapid growth in the resistance of microbial species to antibiotics, there is an urgent need to develop novel materials for biomedical applications capable of providing antibacterial properties without the use of such drugs. Bone healing represents one of the applications with the highest risk of postoperative infections, with potential serious complications in case of bacterial contaminations. Therefore, tissue engineering approaches aiming at the regeneration of bone tissue should be based on the use of materials possessing antibacterial properties alongside with biological and functional characteristics. In this study, we investigated the combination of polyhydroxyalkanoates (PHAs) with a novel antimicrobial hydroxyapatite (HA) containing selenium and strontium. Strontium was chosen for its well-known osteoinductive properties, while selenium is an emerging element investigated for its multi-functional activity as an antimicrobial and anticancer agent. Successful incorporation of such ions in the HA structure was obtained. Antibacterial activity against Staphylococcus aureus 6538P and Escherichia coli 8739 was confirmed for co-substituted HA in the powder form. Polymer-matrix composites based on two types of PHAs, P(3HB) and P(3HO-co-3HD-co-3HDD), were prepared by the incorporation of the developed antibacterial HA. An in-depth characterization of the composite materials was conducted to evaluate the effect of the filler on the physicochemical, thermal, and mechanical properties of the films. In vitro antibacterial testing showed that the composite samples induce a high reduction of the number of S. aureus 6538P and E. coli 8739 bacterial cells cultured on the surface of the materials. The films are also capable of releasing active ions which inhibited the growth of both Gram-positive and Gram-negative bacteria.

scholarly journals Viscoelastic Characterization of Short Fibres Reinforced Thermoplastic in Tension and Shearing

2010 ◽  
Vol 24-25 ◽  
pp. 419-423 ◽  
Author(s):  
A. Andriyana ◽  
Luisa Silva ◽  
Noelle Billon
Keyword(s):  
Mechanical Response ◽  
Polymer Matrix Composites ◽  
Mechanical Analysis ◽  
Integrated Modelling ◽  
Matrix Composites ◽  
Moulding Process ◽  
Permanent Strain ◽  
Mould Filling ◽  
Injection Moulding Process

The present work can be regarded as a first step toward an integrated modelling of mould filling during injection moulding process of polymer matrix composites and the resulting material behaviour under service loading conditions. More precisely, the emphasis of the present research is laid on the development of a mechanical model which takes into account the processing-induced microstructure and is capable to predict the mechanical response of the material. In the Part I, a set of experiments which captures the mechanical behaviour of an injection moulded short fibre reinforced under different strain histories is described. Three mechanical testing are conducted: Dynamic Mechanical Analysis (DMA), uniaxial tension and simple shear. Tests show that the material exhibits complex responses mainly due to non-linearity, anisotropy, time/rate-dependence, hysteresis and permanent strain. Moreover, the relaxed state of the material is characterized by the existence of a so-called anisotropic equilibrium hysteresis independently of the prescribed strain rate.

Azimuthally Scanned Angled-Beam Pulse-Echo Ultrasound for Characterization of Impact Damage in Composites

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
John T. Welter ◽  
Daniel M. Sparkman ◽  
John C. Aldrin ◽  
David Zainey ◽  
Tyler Lesthaeghe ◽  
...  
Keyword(s):  
Polymer Matrix Composites ◽  
Impact Damage ◽  
Slow Crack Growth ◽  
Normal Incidence ◽  
Matrix Composites ◽  
Transverse Cracks ◽  
X Ray Computed ◽  
Ultrasound Inspection ◽  
Pulse Echo

Abstract Characterization of barely visible impact damage (BVID) in polymer matrix composites (PMCs) is necessary to use slow crack growth damage tolerance models and evaluate remaining life of PMC components. Azimuthally scanned angled-beam pulse-echo ultrasound is investigated as a complimentary technique to normal incidence ultrasound inspection of BVID in PMCs to characterize delamination fields. It is found that there is a correlation between signals present in the azimuthally scanned angled-beam pulse-echo ultrasound C-scans and transverse cracks seen in X-ray computed tomography inspection. These transverse cracks are not readily identifiable as transverse cracks in normal incidence C-scan inspection.

Reorientation of carbon nanotubes in polymer matrix composites using compressive loading

2005 ◽  
Vol 20 (4) ◽  
pp. 1026-1032 ◽  
Author(s):  
Michael J. Lance ◽  
Chun-Hway Hsueh ◽  
Ilia N. Ivanov ◽  
David B. Geohegan
Keyword(s):  
Strain Energy ◽  
Polymer Matrix Composites ◽  
Compressive Loading ◽  
Local Strain ◽  
Peak Shift ◽  
Raman Peak ◽  
Matrix Composites ◽  
Raman Peak Shift ◽  
Polarized Raman

Purified single-walled nanotubes (SWNTs) were dispersed in an epoxy polymer and subjected to uniaxial compressive loading. The orientation and stress in the nanotubes were monitored in situ using polarized Raman microscopy. At strains less than 2%, the nanotubes reorient normal to the direction of compression, thereby minimizing the local strain energy. Above 2% strain, the Raman peak shift reaches a plateau. A new analytical model, which approximates the SWNT reorientation by varying the aspect ratio of a representative spheroid, predicted the rotation behavior of nanotubes under load. The results of this model suggest that the observed plateau of the Raman peak shift is caused by both polymer yielding and interfacial debonding at the ends of nanotubes.

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