Levitt-Safety Blog

Understanding Vibration: Definition, Types, and Testing

Jonathan McCallumMarket Segment Manager: Occupational Health, Industrial Hygiene & Environmental MonitoringJuly 10, 2024

What is Vibration?

Vibration, the oscillatory motion of an object around a reference position, is a fundamental concept that impacts a broad spectrum of physical contexts. Its influence is felt in engineering, environmental science, and human health through its diverse forms and effects. Understanding vibration is not just important, it's crucial in these fields and more.

The vibration frequency, measured in Hertz (Hz), represents the number of cycles the vibration completes per second. In contrast, the amplitude represents the maximum distance from the reference position, indicating the extent of the oscillation.

This metric can be observed in a simple mechanical setup like a tuning fork vibrating at a single, precise frequency or a complex assembly like an engine where multiple parts vibrate at various frequencies.

This concept is fundamental to understanding how energy is transmitted through systems in the form of waves and plays a crucial role in fields such as engineering, construction, acoustics, Health & Safety, and materials science.

Understanding vibration frequency helps analyze system behaviours, diagnose issues, and design structures, tools, and equipment to avoid conditions that could lead to component failure or personal injury.

Black and white vibration wave

Types of Vibration

Vibration types can be broadly classified into two main categories: natural and non-natural, each with specific types and effects.

Natural include:

Asphalt road collapsed and cracks in the roadside

Earthquakes: Seismic activities cause ground shaking and affect structures and the earth’s surface.

Windswept tree

Wind: Airflow that can lead to oscillation in structures or objects, influencing engineering designs for buildings and bridges.

Close up detail of powerful teal blue wave breaking in open ocean on a bright sunny afternoon

Ocean Waves: The movement of water that induces vibrations in marine structures is crucial for designing harbours and offshore platforms.

Non-Natural (Man-made) are generated by:

Loading heavy dump truck at the opencast mining

Machines: Vibrations resulting from mechanical movements are vital in monitoring the health and efficiency of industrial equipment.

View of the front of the cars parked in a row

Vehicles: Vibrations caused by engines, road irregularities, and aerodynamic forces impacting vehicle design and construction.

Concert crowd inside a venue, lens flare and smoke are visible

Human Activity: Actions like walking, running, or using tools generate vibrations that influence workplace ergonomics and tool design.

The duration of vibrations further categorizes them into:

  • Short-term: Impacts from hammer strikes or the rapid release of energy in explosions, significant for safety assessments and protective design.
  • Long-term (Continuous): Vibrations from rotating machinery, wind turbines, and traffic affect maintenance schedules and structural durability.

Vibrations also differ by the object they affect:

  • Human Vibration: This includes whole-body and hand-arm vibrations, which can have health implications ranging from discomfort to severe medical conditions.
  • Machine Vibration: Encompasses rotational and reciprocating vibrations, critical for the maintenance and design of machinery.
  • Structure Vibration: Covers resonance and forced vibrations, essential architectural and civil engineering considerations to ensure structural integrity.
  • Ground Vibration: Involves surface and body waves, impacting construction practices and seismic safety measures.

What are Vibration Meters?

Vibration meters are instruments designed to measure the vibration levels and frequencies of machinery, structures, tools, and other objects. These devices are essential for monitoring, analyzing, and diagnosing various systems' health and operational status, helping to identify vibrations that could indicate wear, imbalance, misalignment, and other mechanical or safety issues.

Meters typically quantify vibrations in terms of velocity, displacement, and acceleration, providing data that engineers, technicians and safety professionals use to maintain equipment efficiency, prevent failures and ensure safety. They are widely used in industrial, construction, and engineering settings, where understanding and controlling vibration is crucial to prolonging the lifespan of machinery and structures. They are also used in environmental studies to assess the impact on surroundings and human well-being. 

Types of Sensors Used for Vibration Testing

Vibration testing relies on various types of sensors to measure and analyze the oscillatory movements of machinery. Each sensor type is suited to specific applications and provides different kinds of data. Here are the main types of sensors used in vibration testing:

1. Accelerometers: Accelerometers measure the acceleration of a vibrating object. They are the most used sensors in vibration monitoring, and their versatility makes them suitable for various applications, from industrial machinery maintenance to seismic monitoring.

2. Velocity Sensors: Velocity sensors, also known as velocimeters, measure the velocity of a vibrating object. They are beneficial for detecting low to medium-frequency vibrations.

3. Displacement Sensors: Displacement sensors measure an object's displacement or distance from its resting position. They are valuable in monitoring low-frequency vibrations, such as the health of bridges or buildings.

4. Laser Vibrometers: These sensors use laser beams to measure the velocity and displacement of vibrating surfaces. They provide non-contact measurements, making them ideal for delicate or inaccessible components.

5. Strain Gauges: Strain gauges measure an object's deformation (strain) under vibration. They detect changes in electrical resistance caused by stretching or compressing.

6. Micro-Electro-Mechanical Systems (MEMS): MEMS sensors are miniaturized devices that integrate mechanical and electrical components. They measure acceleration and are known for their small size and low power consumption.

Each type of sensor has its advantages and is chosen based on the specific requirements of the vibration testing task, including the frequency range of interest, the nature of the vibrations, and the environment in which the measurements are to be taken.

By considering factors like the type of machinery, measurement parameters, sensor types, data acquisition requirements, environmental conditions, ease of use, and cost, you can select the best equipment to ensure efficient and effective monitoring.

Levitt-Safety is Canada’s leading occupational health and safety instrument provider for measuring vibration. Choosing the right vibration monitoring equipment involves understanding the specific needs of your machinery, the operating environment, and the critical parameters to be monitored.

Our team of experts is ready to help you find the solution. We can provide product recommendations, quotes and user training to ensure your team gets the best equipment for your needs and applications.

Explore our full range of Vibration Monitoring Equipment here.