國立虎尾科技大學 |

Modeling of Thermo-Mechanical Degradation of Polymer Matrix Composites at High Temperatures.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Modeling of Thermo-Mechanical Degradation of Polymer Matrix Composites at High Temperatures./
Author:	Konduri, Gopala Krishna Teja.
Description:	1 online resource (183 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 84-12, Section: B.
Contained By:	Dissertations Abstracts International84-12B.
Subject:	Mechanical engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9798379660819

Modeling of Thermo-Mechanical Degradation of Polymer Matrix Composites at High Temperatures.
Konduri, Gopala Krishna Teja.

Modeling of Thermo-Mechanical Degradation of Polymer Matrix Composites at High Temperatures. - 1 online resource (183 pages)

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

Thesis (Ph.D.)--The University of Arizona, 2023.

Includes bibliographical references

Carbon fiber reinforced polymer (CFRP) composites are used extensively in aerospace structures due to their high stiffness, strength and low weight. However, these materials have low operational temperatures as their properties are adversely affected by heating. At temperatures above glass transition chemical pyrolysis reactions occur in the polymer leading to the formation of a carbonaceous char residue, and pores filled with pyrolysis gasses. This process, also known as thermal decomposition, leads to an irreversible loss of mass and deterioration of mechanical and thermal properties of the material. Characterizing the behavior of these materials at high temperatures enables the design of structures for severe loading conditions such as lightning strike, laser ablation and fire.In this work micromechanics-based approach is used to predict the effective thermal and mechanical properties of AS4/3501-6 CFRP composite while thermal decomposition occurs. Arrhenius decay law from chemical kinetics is used to create a physics based model to account for the formation of new phases (char and pores) and mass loss in the material. This model enables to create temperature dependent multi-phase Representative Volume Elements (RVE) of CFRP composite at any stage of thermal decomposition. The RVE generated are densely packed with particles randomly distributed and oriented without any directional dependencies.Finite element analysis (FEA) based numerical homogenization procedures for calculating the effective thermal conductivity, specific heat, elastic moduli and coefficient of thermal expansion are developed. The developed procedures are used to calculate the effective properties of AS4/3501-6 composite as a function of temperature and heating rate until the thermal decomposition of the polymer is completed. The calculated effective properties are compared with experimental data from literature and theoretical bounds for multiphase materials.The effects of the decomposition reactions, material phase changes, mass loss and the pressure exerted by the pyrolysis gases trapped in the pores of the material on the effective properties of AS4/3501-6 composite are investigated. Decomposition reactions in 3501-6 polymer are exothermic causing additional heat generation in the material during phase change. A nonlinear transient heat transfer problem is solved at the micro-scale to account for this additional heat generation in the calculation of the effective specific heat.The developed micromechanics based material model is implemented into an FEA analysis of a lightning strike on a CFRP composite. The multi-physic interaction of a lightning current channel with a conductive CFRP laminate is modeled. The model features the effect of Joule heating, spatial and temporal evolution of the lightning current channel, temperature and heating rate dependent material properties, fiber sublimation and material removal. The surface recession and thermal damage of AS4/3501-6 composite subjected to a lightning strike using the developed micromechanics material model and empirical material models from literature is compared with experimental data.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798379660819Subjects--Topical Terms:

557493
Mechanical engineering.
Subjects--Index Terms:

Carbon fiber reinforced polymerIndex Terms--Genre/Form:

554714
Electronic books.

Modeling of Thermo-Mechanical Degradation of Polymer Matrix Composites at High Temperatures.
LDR:04680ntm a22004217 4500 001 1145054
005 20240617111334.5
006 m o d
007 cr mn ---uuuuu
008 250605s2023 xx obm 000 0 eng d
020 $a 9798379660819
035 $a (MiAaPQ)AAI30246378
035 $a AAI30246378
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Konduri, Gopala Krishna Teja. $3 1470264
245 1 0 $a Modeling of Thermo-Mechanical Degradation of Polymer Matrix Composites at High Temperatures.
264 0 $c 2023
300 $a 1 online resource (183 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-12, Section: B.
500 $a Advisor: Zhupanska, Olesya I.
502 $a Thesis (Ph.D.)--The University of Arizona, 2023.
504 $a Includes bibliographical references
520 $a Carbon fiber reinforced polymer (CFRP) composites are used extensively in aerospace structures due to their high stiffness, strength and low weight. However, these materials have low operational temperatures as their properties are adversely affected by heating. At temperatures above glass transition chemical pyrolysis reactions occur in the polymer leading to the formation of a carbonaceous char residue, and pores filled with pyrolysis gasses. This process, also known as thermal decomposition, leads to an irreversible loss of mass and deterioration of mechanical and thermal properties of the material. Characterizing the behavior of these materials at high temperatures enables the design of structures for severe loading conditions such as lightning strike, laser ablation and fire.In this work micromechanics-based approach is used to predict the effective thermal and mechanical properties of AS4/3501-6 CFRP composite while thermal decomposition occurs. Arrhenius decay law from chemical kinetics is used to create a physics based model to account for the formation of new phases (char and pores) and mass loss in the material. This model enables to create temperature dependent multi-phase Representative Volume Elements (RVE) of CFRP composite at any stage of thermal decomposition. The RVE generated are densely packed with particles randomly distributed and oriented without any directional dependencies.Finite element analysis (FEA) based numerical homogenization procedures for calculating the effective thermal conductivity, specific heat, elastic moduli and coefficient of thermal expansion are developed. The developed procedures are used to calculate the effective properties of AS4/3501-6 composite as a function of temperature and heating rate until the thermal decomposition of the polymer is completed. The calculated effective properties are compared with experimental data from literature and theoretical bounds for multiphase materials.The effects of the decomposition reactions, material phase changes, mass loss and the pressure exerted by the pyrolysis gases trapped in the pores of the material on the effective properties of AS4/3501-6 composite are investigated. Decomposition reactions in 3501-6 polymer are exothermic causing additional heat generation in the material during phase change. A nonlinear transient heat transfer problem is solved at the micro-scale to account for this additional heat generation in the calculation of the effective specific heat.The developed micromechanics based material model is implemented into an FEA analysis of a lightning strike on a CFRP composite. The multi-physic interaction of a lightning current channel with a conductive CFRP laminate is modeled. The model features the effect of Joule heating, spatial and temporal evolution of the lightning current channel, temperature and heating rate dependent material properties, fiber sublimation and material removal. The surface recession and thermal damage of AS4/3501-6 composite subjected to a lightning strike using the developed micromechanics material model and empirical material models from literature is compared with experimental data.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2024
538 $a Mode of access: World Wide Web
650 4 $a Mechanical engineering. $3 557493
650 4 $a Polymer chemistry. $3 1182163
650 4 $a Aerospace engineering. $3 686400
653 $a Carbon fiber reinforced polymer
653 $a Aerospace structures
653 $a Pyrolysis gasses
653 $a High temperatures
653 $a Representative Volume Elements
653 $a Finite element analysis
653 $a AS4/3501-6 composite
655 7 $a Electronic books. $2 local $3 554714
690 $a 0548
690 $a 0538
690 $a 0495
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a The University of Arizona. $b Mechanical Engineering. $3 845457
773 0 $t Dissertations Abstracts International $g 84-12B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30246378 $z click for full text (PQDT)