PSI - Issue 45

Thi D. Le et al. / Procedia Structural Integrity 45 (2023) 109–116 "Thi D. Le" / Structural Integrity Procedia 00 (2022) 000 – 000

113

5

2 =− 1+ ( 2 − 2 ) ∗

1 =− 1+ 2 ( 2 − 2 ) ∗

(6)

Where A* and B* are variables that can be calculated by the below equations: ∗ =− ( 2 2 − 1 + 12 + 1 2 ) 12 2 + 2 2 + 1 2 ( +2 )− 1 ∗ =− ( 2 2 − 1 − 12 − 1 2 ) 12 2 + 2 2 + 1 2 ( +2 )− 1

(7)

(8)

Substituting constants C1 and C2 into displacement and stress functions, the new forms of these functions can be expressed as: ( ) = − 1+ 2 2 − 2 [ − ∗ + 2 ∗ ] (9) ( ) = − 1+ 2 − 2 [1− 2 2 ] (10) ( ) = − 1+ 2 − 2 [1+ 2 2 ] (11) ( ) = − 2 1+ 2 − 2 [ (1− 2 2 ) + 1 (1+ 2 2 )] (12) 3. Material properties Mechanical properties of the HDPE and GFRP are calculated from standard tensile tests. 3.1. HDPE The selected PE pipes are Ø20mm, Ø25mm and Ø32mm (SDR 13.6 PE100) manufactured according to AS/ANZ4130. Dimensions of the specimens (coupons) are based on the Standard Test Method for Tensile Properties of Plastics according to ASTM D638-10. A total of 15 coupons (5 coupons for each diameter type) were tested and the Instron 3367 universal testing system are utilized to conduct this tensile test. Table 2 shows the modulus of elasticity (E), yield stress ( y ) obtained from the tensile test. All the data in Table 2 are calculated as an average of 5 samples in each category. The true stress-strain constitutive behavior is plotted in Figure 2. Table 2. Tensile test results for HDPE. Coupon ID Strain rate ( mm/min ) E ( MPa ) ( MPa ) Ø20 50 322.3 21.7 Ø25 50 346.8 22.9 Ø30 50 330.5 22.7 Average 333.2 22.4 3.2. Glass fiber reinforcement Glass fiber composite sheets are cut into 20×250mm rectangular coupons according to the Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials ASTM D3039/D3039M-17. The tensile tests of glass