Why talk about Vibration Analysis?

“Unplanned downtime in Oil and Gas operations can cost millions every year. But how do you predict failures before they happen?”

Unplanned downtime is a challenge Operators face frequently. The answer lies in Vibration analysis. Using a vibration analyser and modern vibration analysing instruments, engineers can monitor the health of the equipment in real time. Combined with simulation, vibration monitoring transforms troubleshooting into foresight, i.e., detecting flaws before they escalate into catastrophic shutdown.

Applications in the Oil & Gas Sector :

Q. What exactly is Vibration Analysis and why does it matter in Oil & Gas?
A. Vibration Analysis is the science of understanding how equipment and structures respond to dynamic forces. In Oil & Gas, where equipment runs continuously under high stress, vibrations often provide first signs of trouble.

Q. Which equipment failures cause the biggest losses?
A. Failures in vertical pump columns, compressors, gearboxes, gas turbines and offshore risers can halt production entirely. A single breakdown doesn’t just cost in repairs, it costs a lot in production, sometimes millions per day.

Q. How does vibration analysis detect problems before they happen?
A. By reviewing the vibration spectrum with a vibration analysis of the system, engineers can spot imbalance, shaft misalignment, looseness or resonance long before failure.

Q. How can vibration monitoring improve safety?
A. Excessive vibration often indicates mechanical weakness that could lead to accidents (e.g. Pump shaft breakage or gearbox failure). Early detection prevents the safety incidents.

Q. Is vibration analysis only for existing equipment?
A. No – Predictive simulations during design stage can avoid future issues. By ensuring structural natural frequencies are safely outside operating frequency ranges, failures can be prevented before operations.

Activities Involved in FEA Vibration Analysis :

A vibration study typically involves:

1. Identifying equipment where FEA vibration analysis is crucial :

• Compressors – Catching imbalance before it damages seals and bearings
• Gearboxes – Spotting gear tooth cracks via vibration patterns
• Gas Turbines – Monitoring blade passing frequencies to prevent catastrophic rotor issues
• Motors & Pumps – Detecting cavitation, shaft misalignment and looseness early
• Offshore Risers & Piping systems – Preventing fatigue failures due to flow-induced vibration

2. Modelling in ANSYS Workbench :

• Creating a detailed 3D or simplified beam/shell model of the equipment along with the supports
• Applying realistic boundary conditions to replicate site conditions

3. Modal Analysis :

• Identifying natural frequencies and mode shapes
• Checking if any natural frequency lies within the operational excitation frequency ranges from source (Motor speeds, fluid pulsations)

4. Harmonic/Forced Vibration Analysis :

• Simulating how the structure responds to dynamic forces
• Reviewing the vibration spectrum to identify resonance risks

5. Evaluation against Industry Standards :

• Comparing results against acceptance criteria (API, ASME, or project-specific guidelines)

6. Recommendations for Mitigation :

• Suggesting stiffener rings, damping solutions, or support modifications to shift critical frequencies away from the operating range

Challenges Typically Faced :

While conducting vibration studies, engineers often encounter :

• Replicating boundary conditions that match site realities (as field constraints differ from design assumptions)
• Limited availability of excitation data such as motor excitation spectrum, soil-structure interaction details, etc.
• Complex coupling between structural dynamics and fluid dynamics within the equipment
• High sensitivity of results to minor changes in geometry or support stiffness

How We Help Solve Vibration Issues :

PMech offers a complete vibration analysis package tailored for critical equipment. Using advanced simulation tools like ANSYS Workbench, we provide:

• Accurate & reliable Modal and Harmonic analysis
• Detailed reporting aligned with international standards
• Design recommendations such as stiffeners, support modifications, or damping solutions
• Proactive vibration monitoring strategies to avoid resonance and increase operational reliability

The result: fewer shutdowns, longer equipment life and safer operations.

Remember: Vibration analysis is not just troubleshooting – it’s foresight. With predictive modelling during design, you can avoid failures, cut costs and keep your assets running reliably.

Looking to reduce unplanned downtime and extend equipment life? Contact PMech today or write to our experts at info@pmecheng.com about how vibration analysis can help your equipment.