The included notch angle machined on a standard Izod impact test specimen measures________________?
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Answer: D. 45°
Explanation
The standard Izod impact test specimen is machined with a 45-degree included notch angle. This precise notch geometry creates a severe triaxial stress state and localized stress concentration during impact testing. Standardizing the 45-degree notch angle ensures repeatable energy absorption measurements across different testing laboratories worldwide. Impact testing evaluates the toughness of engineering materials by measuring the energy absorbed during sudden fracture. The Izod test utilizes a cantilevered specimen clamped vertically while being struck by a swinging pendulum hammer. Notched bar impact testing helps engineers identify materials susceptible to brittle fracture under dynamic shock loading.
Option A (10 degrees) is too narrow and does not conform to standardized international testing protocols for impact specimens. Option B (20 degrees) fails to provide the standard stress concentration geometry specified for conventional Izod testing. Options C and E are incorrect because standard testing specifications universally mandate the 45-degree included notch angle.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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