### Abstract

A micromechanical analysis of the representative volume element (RYE) of a plain weave textile composite has been performed using the finite element method. A previous study by the authors extended a method, known as the Direct Micromechanics Method (DMM), to develop failure envelopes for a plain-weave textile composite under plane stress in terms of applied macroscopic stresses (σ
_{x},σ
_{y}, ι
_{xy}). In the current study, stress gradient effects are investigated, and it is assumed that the stress state is not uniform across the RYE. This is unlike most stiffness and strength models, which start with this premise that there exists an RVE, which is subjected to a uniform stress or strain. However, for textile geometries, nonuniform stress considerations are important, as the size of a textile RYE will typically be several orders of magnitude larger than that of a unidirectional RYE, for which many analysis techniques are developed. Thus a gradient across this dimension could be appreciable. The stress state is defined in terms of the well-known laminate theory load matrices [N], [M], i.e. applied loads and applied moments. Furthermore, structural stiffness coefficients analogous to the [A], [B], [D] matrices are defined. In this approach, these structural stiffness coefficients are computed directly from the micromechanical models, rather than making estimations based upon the homogeneous Young's modulus and plate thickness. Assuming that micro level failure criteria for the yarn and matrix are known, failure envelopes for a plain-weave textile composite have been constructed using microstresses from finite element analysis of the RVE. The predicted values of stiffness and strength compare well to expectable magnitudes. Failure of the fiber tow was the dominant mode of initial failure. The DMM failure envelope compared closely to the Tsai-Wu failure theory, but was more conservative in some areas.

Original language | English (US) |
---|---|

Title of host publication | Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference |

Pages | 4396-4404 |

Number of pages | 9 |

Volume | 6 |

State | Published - 2004 |

Externally published | Yes |

Event | Collect. of Pap. - 45th AIAA/ASME/ASCE/AHS/ASC Struct., Struct. Dyn. and Mater. Conf.; 12th AIAA/ASME/AHS Adapt. Struct. Conf.; 6th AIAA Non-Deterministic Approaches Forum; 5th AIAA Gossamer Spacecraft Forum - Palm Springs, CA, United States Duration: Apr 19 2004 → Apr 22 2004 |

### Other

Other | Collect. of Pap. - 45th AIAA/ASME/ASCE/AHS/ASC Struct., Struct. Dyn. and Mater. Conf.; 12th AIAA/ASME/AHS Adapt. Struct. Conf.; 6th AIAA Non-Deterministic Approaches Forum; 5th AIAA Gossamer Spacecraft Forum |
---|---|

Country | United States |

City | Palm Springs, CA |

Period | 4/19/04 → 4/22/04 |

### Fingerprint

### ASJC Scopus subject areas

- Architecture

### Cite this

*Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference*(Vol. 6, pp. 4396-4404)

**Micromechanical failure analysis of thin plain weave textile composites using the finite element method.** / Karkkainen, Ryan; Sankar, Bhavani V.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference.*vol. 6, pp. 4396-4404, Collect. of Pap. - 45th AIAA/ASME/ASCE/AHS/ASC Struct., Struct. Dyn. and Mater. Conf.; 12th AIAA/ASME/AHS Adapt. Struct. Conf.; 6th AIAA Non-Deterministic Approaches Forum; 5th AIAA Gossamer Spacecraft Forum, Palm Springs, CA, United States, 4/19/04.

}

TY - GEN

T1 - Micromechanical failure analysis of thin plain weave textile composites using the finite element method

AU - Karkkainen, Ryan

AU - Sankar, Bhavani V.

PY - 2004

Y1 - 2004

N2 - A micromechanical analysis of the representative volume element (RYE) of a plain weave textile composite has been performed using the finite element method. A previous study by the authors extended a method, known as the Direct Micromechanics Method (DMM), to develop failure envelopes for a plain-weave textile composite under plane stress in terms of applied macroscopic stresses (σ x,σ y, ι xy). In the current study, stress gradient effects are investigated, and it is assumed that the stress state is not uniform across the RYE. This is unlike most stiffness and strength models, which start with this premise that there exists an RVE, which is subjected to a uniform stress or strain. However, for textile geometries, nonuniform stress considerations are important, as the size of a textile RYE will typically be several orders of magnitude larger than that of a unidirectional RYE, for which many analysis techniques are developed. Thus a gradient across this dimension could be appreciable. The stress state is defined in terms of the well-known laminate theory load matrices [N], [M], i.e. applied loads and applied moments. Furthermore, structural stiffness coefficients analogous to the [A], [B], [D] matrices are defined. In this approach, these structural stiffness coefficients are computed directly from the micromechanical models, rather than making estimations based upon the homogeneous Young's modulus and plate thickness. Assuming that micro level failure criteria for the yarn and matrix are known, failure envelopes for a plain-weave textile composite have been constructed using microstresses from finite element analysis of the RVE. The predicted values of stiffness and strength compare well to expectable magnitudes. Failure of the fiber tow was the dominant mode of initial failure. The DMM failure envelope compared closely to the Tsai-Wu failure theory, but was more conservative in some areas.

AB - A micromechanical analysis of the representative volume element (RYE) of a plain weave textile composite has been performed using the finite element method. A previous study by the authors extended a method, known as the Direct Micromechanics Method (DMM), to develop failure envelopes for a plain-weave textile composite under plane stress in terms of applied macroscopic stresses (σ x,σ y, ι xy). In the current study, stress gradient effects are investigated, and it is assumed that the stress state is not uniform across the RYE. This is unlike most stiffness and strength models, which start with this premise that there exists an RVE, which is subjected to a uniform stress or strain. However, for textile geometries, nonuniform stress considerations are important, as the size of a textile RYE will typically be several orders of magnitude larger than that of a unidirectional RYE, for which many analysis techniques are developed. Thus a gradient across this dimension could be appreciable. The stress state is defined in terms of the well-known laminate theory load matrices [N], [M], i.e. applied loads and applied moments. Furthermore, structural stiffness coefficients analogous to the [A], [B], [D] matrices are defined. In this approach, these structural stiffness coefficients are computed directly from the micromechanical models, rather than making estimations based upon the homogeneous Young's modulus and plate thickness. Assuming that micro level failure criteria for the yarn and matrix are known, failure envelopes for a plain-weave textile composite have been constructed using microstresses from finite element analysis of the RVE. The predicted values of stiffness and strength compare well to expectable magnitudes. Failure of the fiber tow was the dominant mode of initial failure. The DMM failure envelope compared closely to the Tsai-Wu failure theory, but was more conservative in some areas.

UR - http://www.scopus.com/inward/record.url?scp=16244399778&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=16244399778&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:16244399778

VL - 6

SP - 4396

EP - 4404

BT - Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

ER -