Determination of Fracture Toughness by Single and Double Action Tensile Impact Fracture Tests

Abstract:

The characterization of the loading rate dependence of the fracture behavior of polymers is of prime theoretical and practical interest for supporting demanding engineering applications. To gain more insight into the high rate fracture behavior of polymers, fracture tests were performed under tensile loading conditions up to 12 m/s loading rate using a neat model polymer (PVC grey) in this study. A conventional single actuator test set-up for compact tension C(T) specimens was developed based on the previous experience of the authors and implemented on a new high rate servohydraulic testing machine. In addition, a novel double action test set-up was developed by applying two twin actuators and implemented in a rigid horizontal test frame. The conventional load and force measurement was extended by instrumented test specimens and by a high speed optical strain analysis system for both set-ups. Force based fracture toughness values using the peak load values, K_Ic^PL and displacement based values using the critical crack opening displacement (CTOD) K_IC^CTOD were determined up to a loading rate of 10 m/s. While the K_Ic^PL values decreased up to a loading rate 10³ MPam^1/2s^-1 an increase with a high data scatter was observed above them. Corresponding to the CTOD values the calculated K_IC^CTOD values revealed a slight decrease and moderate data scatter up to the maximal loading rate.

• Periodical: Key Engineering Materials (Volume 715)
• Pages: 101-106
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.715.101
• Online since: September 2016
• Authors: Zoltan Major*, Matei Miron, Imre Kallai
• Keywords: Dynamic Effects, Fracture Mechanics of Poolymers, High Rate Testing, High Speed Digitral Image Correlation, Rate Dependent Fracture Toughness

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