The Focal Law Calculator is a specialized tool used in ultrasonic testing and phased array inspection. Its main purpose is to determine the required time delay for each transducer element to focus the ultrasonic beam at a specific point in the material being tested. This process enhances image clarity, improves defect detection, and increases the reliability of nondestructive testing.
This calculator falls under the Ultrasonic Testing / Engineering Tools category. It is essential for professionals in materials science, aerospace, manufacturing, and quality control who rely on accurate, focused wave propagation for inspections.
formula of Focal Law Calculator
Where:
tₙ = Time delay for element n (in seconds)
dₙ = Distance from element n to the focal point (in meters)
d₀ = Distance from the reference (central) element to the focal point (in meters)
c = Speed of sound in the test medium (in meters per second)
The formula helps determine how long to delay the pulse emitted from each transducer element to ensure all waves converge precisely at the intended focal point. This is crucial for beam steering and dynamic focusing in phased array ultrasonic testing.
Commonly Searched Terms Table
| Term | Description |
|---|---|
| Time Delay | Time adjustment for each element to synchronize wave convergence |
| Phased Array | A technique using multiple elements for focused sound beam control |
| Focal Law | A set of time delays calculated to achieve beam focus at a desired point |
| Sound Velocity in Steel | Approximately 5900 m/s; varies by material |
| Delay Law Calculator | Another term often used for focal law calculations |
| Distance to Focal Point (dₙ) | Path length from transducer element to focal point |
| Central Element Distance (d₀) | Path length from reference transducer element to focal point |
| Material Type | Determines speed of sound; affects calculation accuracy |
| Beam Steering | Adjusting delay laws to scan at an angle |
| Focal Point | The specific location in the test material where sound waves are focused |
Example of Focal Law Calculator
Scenario:
You are testing a steel plate using a 16-element phased array probe.
The speed of sound in steel is approximately 5900 m/s.
The distance from element 5 (reference) to the focal point is 30 mm.
The distance from element 1 to the focal point is 33 mm.
Step 1:
Convert all distances to meters:
d₀ = 0.030 m
dₙ = 0.033 m
c = 5900 m/s
Step 2:
Apply the formula:
tₙ = (0.033 − 0.030) / 5900 = 0.003 / 5900 ≈ 5.08 × 10⁻⁷ seconds
Answer:
The required time delay for element 1 is approximately 0.508 microseconds compared to the reference element.
This delay ensures that the ultrasound beams from both elements meet precisely at the focal point for improved detection accuracy.
Most Common FAQs
The focal law is a series of time delays assigned to each element of an ultrasonic array. These delays allow the emitted sound waves to focus at a specific point in the material, improving image resolution and flaw detection.
The speed of sound in the test material affects how quickly ultrasonic waves travel. Different materials (e.g., steel, aluminum, plastic) have different speeds, so using the correct value ensures accurate focal timing.
Yes. By adjusting the focal point to lie at an angle instead of a straight depth, you can calculate delay laws for steering the beam at different angles. This makes it suitable for sector scans and angular inspections.