VibraTec has extensive expertise in vibration analysis and in modal analysis, necessary to perform complete diagnosis campaigns on products or installations in order to identify root causes and propose mitigation actions.

VibraTec is able to mobilize vibration experts on short notice to go on-site (worldwide) with all necessary measurement equipment.

Operating Analysis
Modal Analysis
Contactless Vibration analysis
Stiffness measurements
Vibration Filtration

The goal of analyzing operating equipment is to obtain vibration levels at several points on its structure (machine, package, installation). These vibration analysis results can be compared to criteria from standards (the most common being ISO 10816 for rotating equipment maintenance, MIL STD 810 for vehicle transportation, ISO 8528-9 for power generators and ISO 2631 for human vibration exposition). This information and the time signals obtained are of the utmost importanceto understand and correctly analyze default root causes and be able to propose mitigation to optimize product reliability.

The instrumentation used is composed of sensors able to measure signals using tri-axial accelerometers glued or magnetically attached to specific locations (machine bearings, fixation points, piping, etc). In certain cases, it may be beneficial to complement these vibration level measurements with rotary/instantaneous speed measurements, dynamic force measurements, deformation or displacement measurements, temperature measurements (thermocouple) or dynamic pressure measurements.

magnetic triaxial accelerometers
accéléromètre tri-axes sur palier machine
triaxial accelerometer measurements
dynamic pressure sensor

The measurements are performed at several machine operating regimes; for instance, during run-up, during stabilized operation, or in configurations that provoke critical problems or that require specific measurement result values (often called critical regimes).

The signals from the sensors are digitalized and recorded by an acquisition system in order to obtain the displacements, velocities and/or accelerations at the various measurement points. Appropriate time signal and spectral analyses make it possible to determine the vibration levels. This data is compared to the standards, specifications or VibraTec’s experience. During this time / vibration analysis phase, defaults and abnormal behavior are detected. They are potentially caused by vibrations and indicate a degradation of an element that will require maintenance or specific monitoring (for instance, a bearing default, poor alignment of a rotating shaft, a pulsation phenomenon, etc).

vibration measurement spectrum
spectral vibration analysis

The number of sensors and their positions form a measurement mesh; it is possible to analyze the behavior of the object being diagnosed at the frequencies where high vibration levels are observed. The vibration analysis makes it possible to visualize the way the part subject to vibrations is deformed: this is the Operational Deformation Shape or ODS.

operating deformation shape ODS
ODS operating deformation shape

VibraTec provides training on this subject: please consult our Experimental Vibration Analysis program. Associated programs are also offered: Human Vibration Exposure, Signal Processing.
Contact us for more information regarding vibration analysis, modal analysis, or to discuss a specific problem.

Vibration analysis equipment stopped, also called Experimental Modal Analysis (EMA), serves to determine the natural modes of a structure, machine or piece of equipment. These natural modes are characterized by a specific frequency, a damping and a deformation shape.

Identifying the natural response of a product is an essential part of a thorough diagnosis; the EMA is a necessary complement to an operating vibration analysis.

The principle of these measurements is to apply an excitation over a wide frequency range: the structure or machine’s vibration response is measured with tri-axial accelerometers glued or magnetically attached to strategic points. The excitation can be performed with an instrumented impact hammer, an unbalanced motor, an electrodynamic shaker, a hydraulic jack or even the structure or machine itself.

instrumented shock hammer
modal analysis instrumentation
performing modal analysis
instrumentation vibration excitation

The signals from the sensors and the excitation are digitalized and recorded by an acquisition system that can compute the Frequency Response Functions (FRF: acceleration / force ratio as a function of the frequency). These FRF make it possible to identify the frequency, deformation shape and damping corresponding to the different modes located in the incriminated frequency range.

fonction de réponse en fréquence -FRF

Modal analysis results can be compared to operating vibration analysis results in order to determine if a vibration phenomenon has a structural origin (for instance, the appropriation of a structural mode) or if it comes from an internal machine default (for instance, an unbalance).

VibraTec provides training on this subject: please consult our Experimental Modal Analysis program.

Contact us for more information or to discuss a specific problem.

AME mode shape
AME structural mode

Certain products are too small to be able to use traditional accelerometers; they could significantly influence the product’s dynamic behavior (added mass). In these cases, VibraTec uses other measurement techniques, including a laser vibrometer or miniaturized instrumentation.

laser vibration analysis
miniature modal analysis instrumentation
laser vibration analysis measurements

Modal analysisand operating vibration analysis can be performed with miniature or contactless instrumentation. The signal obtained is analyzed in the same way in order to determine if the problem’s origin is a structural response or a vibration source.

VibraTec provides training on this subject: please consult our Experimental Vibration Analysis and Experimental Modal Analysis programs.

Contact us for more information or to discuss a specific problem.

The principle behind stiffness measurements is to inject an effort in a structure or foundation. The response measured by accelerometers placed at several points provides a signal presenting the force / displacement ratio throughout the frequency range studied. The excitation can be performed with an instrumented shock hammer or an unbalanced motor.

concrete foundation stiffness measurements
civil engineering vibration analysis

This type of measurement serves to validate the stiffness and coherence of a slab, foundation, engineered structures, etc, and also to characterize a structure’s boundary conditions (structures that will host equipment, for instance).

VibraTec provides training on this subject: please consult our Experimental Modal Analysis program.

Contact us for more information or to discuss a specific problem.

Stiffness measurements

It is common to use vibration filtration systems such as anti-vibrating mounts. However, their efficiency is greatly impacted by their dimensioning.

Vibration analysis can be used to validate the efficiency of anti-vibration mounts. Accelerometers are placed upstream and downstream the mounts. The signals obtained are compared in order to confirm the vibration attenuation provided by the mounts.

vibration dampers
vibration damper measurements
anti-vibration mount accelerometer measurements

VibraTec can also define anti-vibration system characteristics following a vibration analysis.

Contact us for more information or to discuss a specific problem.

Vibration Filtration

VibraTec webinars – Electric motor / gearbox sub-assemblies

5 free webinars on electric motor + gearbox sub-assemblies (E-powertrain, electric actuators, gear drives, etc) (given in French with English presentations).