How to Measure Amplitude and Frequency in Vibration Table

Pacorr is known for its advanced and reliable testing instruments designed to ensure the durability and safety of packaging and industrial materials. One of the most critical tools offered by Pacorr is the Vibration Table, which is used to simulate transportation conditions by subjecting products and packaging to vibrations similar to those encountered during road, rail, or air transit. To ensure precise testing, it is essential to measure amplitude and frequency accurately in a Vibration Table. These two factors play a vital role in defining the intensity and impact of vibration testing.

This blog explores in detail how to measure amplitude and frequency in a Vibration Table, the importance of these parameters, and the methods and tools used to achieve accurate readings for quality assurance and compliance with international standards.

Understanding the Functionality of Vibration Table

Before delving into measurement techniques, it’s essential to understand how a Vibration Table works. A vibration table operates by generating oscillatory motion in a controlled manner. The primary objective is to mimic the vibrations that packages experience during transportation. These tests help manufacturers identify weak points in packaging and improve product design to minimize transit damage.

Pacorr’s transport simulation vibration tables offer consistent performance and are widely used in packaging, automotive, electronics, and consumer goods industries to test vibration endurance.

What Is Amplitude in a Vibration Table?

Amplitude refers to the maximum displacement or distance the table moves from its mean position during a vibration cycle. In simpler terms, it is how far the vibration table moves up and down or side to side during each oscillation. This movement is crucial because:

• Higher amplitude means more intense vibration.
• It directly affects the force experienced by the test specimen.
• It simulates more rugged transport conditions.

Amplitude is usually measured in millimeters (mm) or inches, and understanding it helps in choosing the correct vibration severity for specific applications.

What Is Frequency in a Vibration Table?

Frequency refers to how many vibration cycles the table completes per second. It is measured in Hertz (Hz). One Hz equals one cycle per second. Frequency is important because:

• It determines how fast the vibration is occurring.
• Different materials and package types respond differently to various frequencies.
• The resonance of materials may occur at specific frequencies, leading to potential failure.

In vibration testing, both random and fixed frequency modes are used. Fixed frequency is common in repetitive testing, while random frequency helps to replicate real-world vibrations more accurately.

Why Measuring Amplitude and Frequency Matters

Accurate measurement of amplitude and frequency is critical for the following reasons:

• Ensures reliable and repeatable test results.
• Helps in achieving standard compliance such as ASTM D999, ISTA, and ISO 2247.
• Detects design flaws or packaging weaknesses early in the product lifecycle.
• Prevents product returns and reduces customer complaints due to transit damage.

Methods to Measure Amplitude in a Vibration Table

To measure amplitude accurately, the following tools and methods are commonly used:

1. Linear Displacement Sensors

These sensors are placed on the surface of the vibration table to detect movement. They provide accurate digital readings of the displacement occurring during vibration cycles.

2. Rulers or Vernier Calipers (Manual)

For basic setups, a manual method can be used by placing a vertical reference scale next to the vibrating platform and visually observing the displacement. However, this method lacks precision.

3. Laser Displacement Sensors

Advanced vibration tables may use laser-based sensors that can measure very fine displacements without any physical contact. This method offers high accuracy and is suitable for sensitive measurements.

4. Accelerometer Data Interpretation

By interpreting the signal from an accelerometer using mathematical formulas, amplitude can be calculated. This method is often combined with software to process vibration signals.

Methods to Measure Frequency in a Vibration Table

Measuring frequency involves determining the number of oscillation cycles per second. The tools and techniques include:

1. Digital Frequency Meters

These are connected to the vibration controller system and directly display the frequency of oscillation. They are highly accurate and preferred in industrial applications.

2. Oscilloscopes

Oscilloscopes display the waveform of the vibration signal in real time. By analyzing the wave pattern, the frequency can be calculated. This method is useful for both fixed and random frequency testing.

3. Vibration Analyzers with FFT (Fast Fourier Transform)

Advanced analyzers use FFT algorithms to break down complex vibration signals into individual frequencies. These devices are ideal for comprehensive analysis in multi-axis vibration testing.

4. Accelerometers with Data Loggers

Using triaxial accelerometers attached to the vibrating surface, data can be collected and analyzed using software to determine the vibration frequency and pattern over time.

Step-by-Step Guide to Measure Amplitude and Frequency in Vibration Table

Here’s a quick step-by-step guide to measuring both amplitude and frequency:

Step 1: Turn on the Vibration Table and set your desired testing parameters using the controller.

Step 2: Mount a calibrated accelerometer or displacement sensor on the surface of the table or on the sample.

Step 3: Run the table and observe the real-time values on your vibration analyzer or frequency meter.

Step 4: Record the peak-to-peak displacement (for amplitude) and the number of cycles per second (for frequency).

Step 5: If using software, export the data for further analysis and comparison against standard testing protocols.

Common Standards Related to Amplitude and Frequency Measurement

Several international testing standards govern vibration testing and define acceptable ranges for amplitude and frequency. These include:

• ASTM D999 – Vibration testing of shipping containers.
• ISO 2247 – Packaging, vibration testing under laboratory conditions.
• ISTA Procedures – Vibration simulation tests for packaged products.
• MIL-STD-810 – Environmental engineering considerations and laboratory tests (used in defense applications).

Using Pacorr’s Vibration Table helps users easily align with these standards due to the product's precision and adaptability.

Best Practices for Accurate Vibration Testing

• Calibrate sensors and analyzers before starting the test.
• Ensure that the vibration table surface is level and securely mounted.
• Use non-slip pads or fixtures to keep the specimen in place.
• Keep the ambient conditions stable to avoid test interference.
• Repeat the test multiple times to verify repeatability.

Industries That Rely on Precise Vibration Testing

Vibration testing is critical for many industries including:

• Packaging and Logistics – To test box integrity and reduce transit damage.
• Automotive – To ensure vehicle components withstand road vibrations.
• Electronics – For testing PCBs, batteries, and other fragile components.
• Pharmaceuticals – To confirm the safety of sealed containers during shipping.
• Consumer Goods – To test durability and performance of everyday products.

Pacorr’s vibration testing solutions are extensively trusted in these sectors due to their reliability and precision in measuring amplitude and frequency.

Conclusion

Pacorr’s Vibration Table is a powerful tool for simulating real-world transport conditions and ensuring product integrity. Accurately measuring amplitude and frequency is essential to validate test results and align with international quality standards. By using proper sensors, analyzers, and measurement techniques, manufacturers can achieve greater confidence in their product's performance under transit stress. Regular vibration testing with precision instrumentation leads to better packaging design, fewer product returns, and improved customer satisfaction.