PSI - Issue 21

Hande Yavuz / Procedia Structural Integrity 21 (2019) 112–119 H. Yavuz/Structural Integrity Procedia 00 (2019) 000 – 000

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Abaqus v6.14 (Abaqus 2012) for the damage evaluations of unnotched laminates. Moreover, the failure behavior of various notched laminates was also analyzed using Hashin’s built -in model in Abaqus v6.14.

Nomenclature ASTM

American Society for Testing and Materials Cambridge Engineering Selector Composite Materials Handbook Hashin’s Tensile Fiber Failure Criteria Hashin’s Compressive Fiber Failure Criteria Hashin’s Tensil e Matrix Failure Criteria Hashin’s Compressive Matrix Failure Criteria Fracture toughness, tensile mode of Preliminary Material Properties Handbook Quasi-isotropic laminate; [0/+45/-45/90] Symmetric laminate; [+45/+30/0/90] s Symmetric balanced laminate; [+45/-45/0/90] s Polyether ether ketone

CES

CMH-17

HSNFTCRT HSNFCCRT HSNMTCRT HSNMCCRT

K 1c

MMPDS

Metallic Materials Properties Development and Standardization

PEEK

PMP-HDBK

QI

SYM SYMB

2. Materials and Method 2.1. Materials selection for skin panels

The material selection for a skin panel in an aircraft was carrie d out using Ashby’s multiple constraints methodology. Since the objective of this design is the minimization of mass, materials selection for a skin panel have to be considered by covering both limitation cases as strength and stiffness as represented in Table 1.

Table 1. Material selection requirements for a skin panel in an aircraft Function Skin panel (bending plate) Objective Minimize mass Constraints

Must not fail (yielding/fracture) under load, F (constraint 1) Must have specified stiffness, S (constraint 2) Length L and bending moment M are specified Must have adequate fracture toughness, K 1c > 15 MPa·m 1/2

Free variables Choice of material Panel thickness, t

By introducing relevant equations for constructing stiff, strong, and light panel design, the coupling constant was used to identify the candidate materials depending on the safety performances using CES Edupack software. K 1c for the structural materials must be higher than 15 MPa · m 1/2 (Ashby 2011), thus the materials which have lower adequate fracture toughness were eliminated from the graph where the families of composites, metals and metal alloys were included accordingly (Figure 1). For skin panels, best candidate materials were determined as cyanate ester/carbon fiber, PEEK/carbon fiber, epoxy/carbon fiber, epoxy/aramid fiber, epoxy/glass fiber. Since epoxy/carbon fiber composites preserve their high strength and stiffness at low densities, they become highly desirable for such component designs. Among the candidate materials, elastic and strength properties are readily available for AS4/3502 in CES EduPack software. Thus, these data were withdrawn from CES Edupack software for the computational damage analysis in various laminated