Element Materials Technology
Choosing a Vibration Testing Procedure
This article first appeared in the Railway-News magazine, Issue 4 2022 Data & Monitoring edition.
From validating product design and establishing operational limits to qualifying equipment based on customer or industrial standards, vibration testing is a valuable tool for manufacturers, designers and engineers.
In general, vibration testing is used to demonstrate a product’s ability to resist dynamic loads without losing critical functional or structural integrity under specified loads. It can be used to identify accumulated stress effects, and the resulting mechanical weaknesses and performance flaws.
Choosing the right vibration testing protocol helps ensure that products can safely withstand the vibration levels they experience throughout their service life, ensuring product quality and safety. While most standards provide generic default test severities, more advanced procedures use existing data from product performance and operational environments to better replicate in-service conditions.
Understanding Different Vibration Testing Procedures
There is a wide range of vibration testing procedures available, each with unique features and benefits. While they all share similarities, the primary differentiating factor is the type of excitation created by each method. The pattern, rhythm and dwell of vibration testing procedures help determine which method is best-suited to replicate real-world conditions and ensure product quality.
Sinusoidal (Sine) Vibration
The simplest vibration testing procedure, sine vibration testing, uses a single sinusoidal tone following simple harmonic motion input to the test specimen. This sinusoidal tone can be swept across the test frequency range, or it can be fixed on a single frequency, depending on the requirement.
Sinusoidal testing stimulates a test specimen’s natural structural (resonance) frequencies of vibration. Test frequency can be selectively varied to focus on natural frequencies of interest. Swept sinusoidal testing using lower acceleration levels is typically used to perform resonance searching (vibration response investigation) to identify resonance frequencies present in the test specimen.
