PSI - Issue 47

2

Rachid Bensaada et al. / Procedia Structural Integrity 47 (2023) 503–512 R. Bensaada et al. / Structural Integrity Procedia 00 (2019) 000 – 000

504

Nomenclature E 1

Longitudinal modulus Transversal modulus

E 2 σ L σ T

Longitudinal stress threshold Transversal stress threshold

Nu 12 G 12 G 13 G 23

L- T Poisson’s ratio x-y Shear modulus x-z Shear modulus y-z Shear modulus

Τ L Τ T G f T S

Longitudinal shear stress threshold Transversal shear stress threshold Critical strain energy release rate

Ultimate strength for cohesive element separation

L c Characteristic element length Interlaminar tensile stress Interlaminar shear stress Experimental average tensile stress Experimental average shear stress 1. Introduction

UHMWPE (Ultra High Weight Poly-Ethylene) composites are recognized for their impact resistance (Karthikeyan et al. 2013)(Russell et al. 2013). Unlike fiber-epoxy composites, UHMWPE composites are composed of a succession of precursor plies that are pressed and heated according to a defined cycle (Alil et al. 2018). Despite of the interesting performances exhibited by these materials when exposed to high strain rate solicitations, improvements are possible and could conduct to structural optimization (weight reduction, improvement of materials properties) by multi -material assembly or hybridization. The efficiency of this method is proven, especially under dynamic loading solicitations (Sapozhnikov, Kudryavtsev, and Zhikharev 2015)(Zulkifli et al. 2019). Recently, Hybridization of Tensylon® was achieved successfully by means of thermal spraying (Bensaada et al. 2023). An Al 2 O 3 coating was deposited on Tensylon® substrate including a Zn intermediate layer. The materials (coated and uncoated), testing under laser adhesion test, show a significant improvement by thermal spray coating (rear face velocity reduced by more than half). For a sake of a better material behavior knowledge, its quasi-static response should be determined, notably in its out-of-plane direction, given the application for which is dedicated for. The first step consists of the characterization of the Tensylon® as provided by DuPont© through the out-of-plane direction. Within the literature, many options are available to evaluate the out-of-plane properties of composites or interlaminar strength, however, not all these methods are suitable to achieve the targeted results of the present study. Indeed, standardized tests as DCB (ASTM D5528/D5528M-21 2022), ENF (ASTM D7905/D7905M-19e1 2019) and MMB (ASTM D6671/D6671M-22 2022) require a notch in the specimen design as a crack initiation. This influences the crack propagation and skew the targeted predictions. Other non-standardized tests, such as Scarf (Liao, Huang, and Sawa 2013) include edge effect and complex triaxial stress at the edge of the assembly. To overcome the aforementioned limitations, the modified Arcan device developed by Cognard et al. (Cognard et al. 2005) basedon the works of Arcan et al. (Arcan, Hashin, and Voloshin 1978) is used. The efficiencyof this method is proven, notably in the assessment of the strength of composites (Alfonso et al. 2015)(Sohier, Cognard, and Davies 2013). The aim of this work is to investigate the response to failure of Tensylon® following a wide range of stress