Jacques W. Nader

Probabilistic Finite Element Analysis of Modified ASTM D3039 Tension Test for Marine Grade Polymer Matrix Composites

The variability of tensile mechanical properties of a polymer matrix composite material with woven fabric reinforcement is studied using both experimental work and numerical simulations. Four E-glass/vinyl ester composite plates were fabricated using the vacuum-assisted resin transfer molding (VARTM) by a US Navy contractor. The materials and process selected are representative of Marine grade composites typically used by the US Navy. Standard and modified D3039 tensile coupons were obtained from the plates and the laboratory results were compared with those of a 3D probabilistic finite element analysis (FEA). In the probabilistic FEA model, elastic properties, strength parameters, and geometric properties of the woven fabric E-glass/vinyl ester coupons were considered as random fields, and generated using Monte Carlo simulations. The study evaluates the effects of spatial correlation, finite element size, probability distribution functions (PDF) types, and failure criteria on statistical strength properties of the [(0w/90f)/(0f/90 w)]2s tension coupons. Comparisons of experimental and probabilistic FEA results provide useful information on how to assign mean, COV, and PDF of material properties to individual finite elements within a mesh. The results are relevant in developing design properties for these composites.

Size effects on the bending strength of fiber-reinforced polymer matrix composites

This article investigates the size effects associated with length and width, on the bending strength of marine grade polymer matrix laminated composites. A new expression for predicting the strength size effect was developed and was verified using both laboratory testing and probabilistic finite element analysis (FEA). Woven [0/45/—45/0]5sf E-glass/vinyl ester material specimens with different lengths and widths and same thickness were evaluated to predict the effect of specimen size on the bending strength. In the probabilistic FEA models, elastic properties (E11, E22, G12, υ12), and strength parameters (F1t, F1c, F2t , F2c, F6, ε1t, ε 1c, ε2t, ε2c, ε12) of the woven fabric E-glass/vinyl ester ASTM D6272 coupons were considered as random fields, and generated using Monte Carlo simulations. The relationship between the bending strength and specimen size of the [0/45/—45/0]5sf lay-up was also evaluated experimentally. Thirty-two material specimens were prepared and tested according to ASTM D6272 using combinations of two span-to-thickness ratios (32 : 1 and 16 : 1), and two width-to-thickness ratios (3 : 1 and 1.5 : 1).

Probabilistic Finite Element Analysis of ASTM D6641 Compression Test for Marine Grade Polymer Matrix Composites

The variability of compressive mechanical properties of a polymer matrix composite material with woven fabric reinforcement is studied using both experimental work and numerical simulations. Four E-glass/vinyl ester composite plates were fabricated using the vacuum-assisted resin transfer molding (VARTM) by a US Navy contractor. The materials and process selected are representative of marine grade composites typically used by the US Navy. Standard ASTM D6641 coupons were obtained from the plates and the laboratory results were compared with those of a 3D probabilistic finite element analysis (FEA). In the probabilistic FEA model, elastic properties, strength parameters and geometric properties of the woven fabric E-glass/vinyl ester coupons were considered as random fields, and generated using Monte Carlo simulations. The study evaluates the effects of spatial correlation, finite element size, probability distribution functions (PDF) types and failure criteria on statistical strength properties of the [0/90]2sf compression coupons. Comparisons of experimental and probabilistic FEA results provide useful information on how to assign mean, Coefficient of variance (COV) and PDF of material properties to individual finite elements within a mesh. The results are relevant in selecting proper test methods and developing design properties for these composites.

Strength Performance of Prestressed Glass Fiber–Reinforced Polymer, Glued-Laminated Beams

This article focuses on assessing the strength performance of glued-laminated (glulam) beams with E-glass fiber–reinforced polymer (GFRP) prestressing (prestressed GFRP-glulam beams) through bendin...