TY - BOOK

T1 - Reinforcement of elastomers to obtain anisotropic material properties

AU - Beter, Julia

N1 - embargoed until null

PY - 2021

Y1 - 2021

N2 - The demand of fiber reinforced elastomers representing a new material class with unique capabilities is constantly growing. By constituting hyperelastic elastomers as interesting matrix material, these flexible composites with direction-dependent behavior allows the development of tailored stimuli-responsive properties triggered by load coupling effects like tension-twist or bending-twist mechanisms. The state of the art regarding the comprehensive material characterization for fiber reinforced elastomers and their load coupling effects showed that current findings for material-specific and suitable test concepts are still barely analyzed. Thus, the objective of this thesis is to provide profound knowledge of the material behavior, reliable testing possibilities and functional solutions concerning fiber reinforced elastomers especially for potential smart composite applications. Therefore, a systematic simplification of a test chain from micro- to macromechanical characterization is realized. A suitable step-by-step principle with conclusive transfer criteria are implemented. Due to the significant influence of the fiber-matrix interaction on the composite performance, the fiber-matrix adhesion and interfacial properties are investigated using fiber debond techniques including further tailored surface treatments to prove the impact on the adhesion. Regarding the material characterization exposed to cyclic loading by dynamic mechanical and step cycle analysis, the investigation of the energy absorption capacity, dynamic properties and force redirecting ability leading to load- and time-dependent behavior is necessary. Another part is the study of load coupling mechanism and the development and verification of a suitable material-related test concept. Based on the findings from the developed test chain especially for fiber reinforced elastomers, the need of correct transfer criteria for a systematic step-by-step simplification and the importance of precise material data evaluation due to their significant effects on the fiber-matrix interaction was demonstrated. Overall, the fiber bundle pull-out test can be considered as intermediate step representing a link between micro- to macromechanical testing enabling an adequate material study on the fiber-matrix adhesion performance. For the tension-twist load coupling characterization, the verification of the novel test concept offers a promising basis to investigate mechanical triggered load-coupling effects.

AB - The demand of fiber reinforced elastomers representing a new material class with unique capabilities is constantly growing. By constituting hyperelastic elastomers as interesting matrix material, these flexible composites with direction-dependent behavior allows the development of tailored stimuli-responsive properties triggered by load coupling effects like tension-twist or bending-twist mechanisms. The state of the art regarding the comprehensive material characterization for fiber reinforced elastomers and their load coupling effects showed that current findings for material-specific and suitable test concepts are still barely analyzed. Thus, the objective of this thesis is to provide profound knowledge of the material behavior, reliable testing possibilities and functional solutions concerning fiber reinforced elastomers especially for potential smart composite applications. Therefore, a systematic simplification of a test chain from micro- to macromechanical characterization is realized. A suitable step-by-step principle with conclusive transfer criteria are implemented. Due to the significant influence of the fiber-matrix interaction on the composite performance, the fiber-matrix adhesion and interfacial properties are investigated using fiber debond techniques including further tailored surface treatments to prove the impact on the adhesion. Regarding the material characterization exposed to cyclic loading by dynamic mechanical and step cycle analysis, the investigation of the energy absorption capacity, dynamic properties and force redirecting ability leading to load- and time-dependent behavior is necessary. Another part is the study of load coupling mechanism and the development and verification of a suitable material-related test concept. Based on the findings from the developed test chain especially for fiber reinforced elastomers, the need of correct transfer criteria for a systematic step-by-step simplification and the importance of precise material data evaluation due to their significant effects on the fiber-matrix interaction was demonstrated. Overall, the fiber bundle pull-out test can be considered as intermediate step representing a link between micro- to macromechanical testing enabling an adequate material study on the fiber-matrix adhesion performance. For the tension-twist load coupling characterization, the verification of the novel test concept offers a promising basis to investigate mechanical triggered load-coupling effects.

KW - intelligenter Verbundwerkstoff

KW - intelligente Werkstoffe

KW - flexibler Verbundwerkstoff

KW - faserverstärktes Elastomer

KW - Lastkopplungsmechanismus

KW - Viskoelastizität

KW - Faser-Matrix Grenzfläche

KW - Faser-Matrix Haftung

KW - Oberflächenmodifikation

KW - chemische Modifizierung

KW - Grenzflächen

KW - Faserbündel-Auszugsversuch

KW - Faserauszug

KW - Faser-Matrix Lösverfahren

KW - smart composite

KW - smart material

KW - flexible composite

KW - fiber-reinforced elastomer

KW - load-coupling mechanism

KW - viscoelasticity

KW - fiber–matrix interface

KW - fiber‐matrix adhesion

KW - surface modification

KW - chemical sizing

KW - interface

KW - fiber bundle pull-out test

KW - fiber pull-out

KW - fiber‐matrix debond technique

M3 - Doctoral Thesis

ER -