PSI - Issue 17

C P Okeke et al. / Procedia Structural Integrity 17 (2019) 589–595 C P Okeke et al / Structural Integrity Procedia 00 (2019) 000 – 000

593

5

40mm

10mm

25mm

3mm

Clamped area

5mm

4mm

10mm

2mm

170mm

2.86mm

Figure 2: Test specimen dimensions

Specimen

Test fixture

Vibration shaker

Figure 3: Test set-up

5. Results and discussion

5.1. Experimental results

Tensile testing was performed to obtain the tensile elastic properties. The elastic properties were based on the average of the ten specimens tested. The tensile yield stress which is usually about the same as the ultimate tensile strength and the poisons ratio are 62MPa and 0.42 respectively. The elastic modulus which defines the material stiffness was obtained across the stress as shown in fig 4. The curve clearly shows the evidence of nonlinearity in PMMA material within the elastic limit. As the stress increases, the elastic modulus decreases, and the rate of decrease is higher from 28MPa to the peak stress. The calculated initial elastic modulus and the secant modulus are 3210MPa and 1961MPa, these values are highlighted on the curve.

Figure 4: Elastic modulus variation across the stress