Impact Test Calculator
Free calculate impact energy from charpy and izod impact tests. determine material toughness and impact resistance.
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Results
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What is an Impact Test?
An impact test measures a material's ability to absorb energy during sudden loading or impact. The two most common types are the Charpy and Izod impact tests, which use a swinging pendulum to strike a notched specimen.
Impact energy is calculated from the difference in potential energy of the pendulum before and after impact. Higher impact energy indicates better toughness and resistance to brittle fracture.
Impact testing is essential in material science, quality control, and engineering to ensure materials can withstand sudden shocks and impacts in real-world applications.
Impact Test Formulas
Impact Energy
From pendulum heights
Impact Strength
Energy per unit area
How to Calculate
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1
Measure pendulum parameters
Record pendulum mass, initial height, and final height after impact.
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2
Calculate energy absorbed
E = m × g × (h_i - h_f), where g = 9.81 m/s².
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3
Calculate impact strength (optional)
Divide energy by specimen cross-sectional area at the notch.
Practical Examples
Example 1: Charpy Test
A 30 kg pendulum starts at 1.5 m and ends at 0.5 m after breaking a specimen. Calculate impact energy.
Solution:
E = m × g × (h_i - h_f) = 30 kg × 9.81 m/s² × (1.5 - 0.5) m
E = 294.3 J
Example 2: Impact Strength
Impact energy is 50 J for a specimen with 0.0001 m² cross-section. Calculate impact strength.
Solution:
σ_impact = E / A = 50 J / 0.0001 m²
σ_impact = 500,000 J/m² = 500 kJ/m²
Applications
Material Testing
Quality control, material selection, and ensuring materials meet toughness requirements for applications.
Automotive
Testing materials for crash safety, ensuring components can withstand impact loads in accidents.
Construction
Evaluating steel and concrete toughness for structures that must resist dynamic loads and impacts.
Research
Studying material behavior, fracture mechanics, and developing tougher materials for various applications.
Frequently Asked Questions
What is the difference between Charpy and Izod tests?
Charpy: specimen is horizontal, struck on the side opposite the notch. Izod: specimen is vertical, struck at the top. Both measure impact energy but with different specimen orientations.
Why use a notched specimen?
The notch creates a stress concentration, making the test more sensitive to brittle fracture. It simulates real-world flaws and stress risers in materials.
What does high impact energy mean?
High impact energy indicates ductile, tough material that can absorb energy before fracturing. Low impact energy indicates brittle material that fractures easily.
How does temperature affect impact energy?
Many materials show a ductile-to-brittle transition. At low temperatures, impact energy decreases significantly, making materials more prone to brittle fracture.
What are typical impact energy values?
Ductile steel: 50-200 J, brittle steel: 5-20 J, plastics: 1-50 J, ceramics: <1 J. Values depend on material, temperature, and notch geometry.