Impact Test Calculator
Calculate energy absorption in Charpy and Izod impact tests for material toughness analysis
Impact Test Configuration
Charpy Impact Test: Simply supported beam configuration
Standards: ASTM D6110 (Plastics), ASTM E23 (Metallic)
Pendulum Angles
Initial pendulum position (before release)
Final pendulum position (after impact)
Physical Parameters
Distance from center of rotation to striker
Mass of the hammer/anvil
Energy lost to friction, vibration, etc.
Specimen Properties (Optional)
Impact Test Results
Example Calculation
Charpy Impact Test
Test Setup: Steel specimen impact testing
Angle of fall (β): 60°
Angle of rise (α): 30°
Pendulum length (S): 1.0 m
Striker mass (m): 0.44 kg
Energy loss (E_l): 0 J (assumed negligible)
Calculation Steps
1. Initial height: h = 1.0 × (1 - cos(60°)) = 1.0 × (1 - 0.5) = 0.5 m
2. Final height: h₁ = 1.0 × (1 - cos(30°)) = 1.0 × (1 - 0.866) = 0.134 m
3. Energy absorbed: E = 0.44 × 9.8067 × (0.5 - 0.134) = 1.58 J
4. Impact velocity: V = √(2 × 9.8067 × 0.5) = 3.13 m/s
5. Result: Material absorbed 1.58 J of impact energy
Test Type Comparison
Failure Modes
Typical Impact Energy
Testing Tips
Higher energy absorption = higher toughness
Notch creates stress concentration
Temperature affects impact resistance
Account for energy losses
Follow ASTM testing standards
Understanding Impact Testing
What is Impact Testing?
Impact testing is a method used to evaluate the energy absorption capacity and fracture toughness of materials under dynamic loading conditions. The test simulates sudden impact or shock loading that materials might experience in service, helping engineers understand how materials behave under rapid force application.
Test Methods
The two most common impact tests are the Charpy and Izod tests, both using pendulum-based impact machines. The key difference lies in specimen orientation: Charpy tests use simply supported specimens struck at the center, while Izod tests use cantilever specimens struck near the free end.
Applications
- •Material Selection: Choosing materials for impact-prone applications
- •Quality Control: Verifying material properties in production
- •Temperature Effects: Studying brittle-ductile transition
- •Safety Analysis: Predicting failure in dynamic loading
Energy Calculation Formulas
Pendulum Heights
h = S(1 - cos β)
h₁ = S(1 - cos α)
where S = pendulum length, β = fall angle, α = rise angle
Energy Absorbed
E = mg(h - h₁) - E_l
E = absorbed energy, m = striker mass, g = gravity, E_l = energy losses
Impact Velocity
V = √(2gh)
Velocity of striker just before impact
Important: Impact energy absorption is a critical measure of material toughness and helps predict how materials will behave under sudden loading conditions such as crashes, drops, or explosions.