Department News
3-D Analysis of Woven Composites
Seminar Date
2001-03-21
Author
손문숙
Date
2001-03-21
Views
1366
1. 제 목 : 3-D Analysis of Woven Composites
2. 연 사 : 신 상욱 박사
Research Engineer
Wright-Patterson Air Force Materials Lab
3. 일 시 : 2001년 3월 19일 (월) 16:00 – 17:00
4. 장 소 : 301동 1512호
5.내 용 :The failure in textile composites in general occurs in the vicinity of two perpendicular yarn crimping over and under to each other. In the vicinity of the yarn crimping, the stress is three-dimensional. In-situ experimental observation of damage initiation in textile composites reveals that the damage initiates in the form of interface cracks in the vicinity of yarn crimping, which is strongly influenced by the interlaminar stresses at the interface region. Therefore, an accurate prediction of the interlaminar stresses at the interface region is essential to reliably analyze damage and failure in woven composites.
Two analysis methods are developed to obtain reliable calculation of the interlaminar stresses at the yarn interface: The first method is a mixed finite element analysis based on Reissners mixed variational principle, whose variational energy takes independent variation on stresses and displacements. The interfacial traction continuity conditions are achieved through a penalty approach. The second one is a B-Spline Analysis Method (B-SAM), which employs overlapping m-th order B-spline approximation functions of displacements, and thus achieves continuous evaluation of the stresses and strains as well as the displacements in each homogenous domain (yarn or matrix in the case of woven composite). Numerical solutions from both methods obtained for flat-laminate free-edge problem and plain-weave laminated composites yield the reliable interlaminar stress calculation at the yarn interfaces, except at high stress gradient due to stress singularity from material discontinuity.
6. 문 의 : 기계항공공학부 이 우 일 교수 (☏ 880-7116)
2. 연 사 : 신 상욱 박사
Research Engineer
Wright-Patterson Air Force Materials Lab
3. 일 시 : 2001년 3월 19일 (월) 16:00 – 17:00
4. 장 소 : 301동 1512호
5.내 용 :The failure in textile composites in general occurs in the vicinity of two perpendicular yarn crimping over and under to each other. In the vicinity of the yarn crimping, the stress is three-dimensional. In-situ experimental observation of damage initiation in textile composites reveals that the damage initiates in the form of interface cracks in the vicinity of yarn crimping, which is strongly influenced by the interlaminar stresses at the interface region. Therefore, an accurate prediction of the interlaminar stresses at the interface region is essential to reliably analyze damage and failure in woven composites.
Two analysis methods are developed to obtain reliable calculation of the interlaminar stresses at the yarn interface: The first method is a mixed finite element analysis based on Reissners mixed variational principle, whose variational energy takes independent variation on stresses and displacements. The interfacial traction continuity conditions are achieved through a penalty approach. The second one is a B-Spline Analysis Method (B-SAM), which employs overlapping m-th order B-spline approximation functions of displacements, and thus achieves continuous evaluation of the stresses and strains as well as the displacements in each homogenous domain (yarn or matrix in the case of woven composite). Numerical solutions from both methods obtained for flat-laminate free-edge problem and plain-weave laminated composites yield the reliable interlaminar stress calculation at the yarn interfaces, except at high stress gradient due to stress singularity from material discontinuity.
6. 문 의 : 기계항공공학부 이 우 일 교수 (☏ 880-7116)
