PSI - Issue 14

Aisha Ahmed et al. / Procedia Structural Integrity 14 (2019) 507–513 Aisha Ahmed/ Structural Integrity Procedia 00 (2018) 000–000

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Table 2. Dynamic mechanical properties obtained from typical SHPB data at limiting strain rate.

Strain Rate (s -1 )

Strain (at Peak Stress)

Peak Stress (MPa)

Toughness at Yield (MPa)

Toughness at Peak Stress (MPa)

Composition

PC

8519

290.71 361.07 343.41 449.74

56.38 95.88

0.295 0.468 0.481 0.611

0.663

PCA5

11514 10783 13252

1.32 7.99 11.9

109.32 129.90

PCA/CNT1 PCA/CNT5

i Q d 

   

Toughness ,

(4)

0

i 

0 

d   

E



(5)

Energy absorption efficiency ,

i

From the Fig. 3, it can be evaluated that energy absorption efficiency very quickly attains a maximum value (at about 0.1 strain) and roughly remained constant during the impact and gradually drops when maximum strain is achieved. Also, PCA/CNT5 showed the maximum efficiency to absorb energy which can be attributed to the presence of MWCNT reinforcement. Hence, MWCNT is also a candidate for reinforcing the matrix material to dissipate energy with no substantial increase in weight.

Fig. 3. Energy absorption efficiency of different PC compositions at limiting strain rate.

4. Summary & Conclusion In this study the following inferences can be drawn from the dynamic compressive experiments:  PC has shown a positive toughening effect through blending with methyl acrylate and MWCNTs.  Ductile failure proved to be good for the confinement of the ceramic as it increases the dwell time.  The energy absorption efficiency improves from 0.4 % to 0.65% and attains nearly a constant value before failure, which is good but can be improved further.  The limiting strain rate increased from 8519 /s for neat PC to 11514 /s for PCA5 and to 13252 /s for the PCA/CNT5 (nano-composite).  Peak stress increases with increase in strain rate for a single composition and also 24 % increased for PCA5 from neat PC and 55% for the PCA/CNT5, at a maximum strain of 0.6.