LamaLo Technology Inc.

Propulsion Shaft Vibration

Marine propulsion shaft vibration measurement and analysis is a core part of LLT’s business. With respect to existing vibration problems, we take a Systems Engineering approach. All aspects of the shaftline vibration and alignment are investigated by using a combination of analytical modeling, on-site measurements, documentation review, and analysis of the operating environment, bearing/seal design and shipyard construction practices. Documented case studies and previous experiences are referenced in the assessment. A least-cost solution is sought. The US Coast Guard Standards for the "Evaluation of Ship Propulsion Machinery Vibration" are used as a guide for the testing and analysis; however, the testing will be conducted according to client’s specific requirements.

Theoretical Modeling

A formal Engineering Shaftline Vibration Analysis Report is produced, and includes the following:

Description of modeling technique and parameters used in the analysis

Natural Frequencies of Vibration (Torsional, Axial, and Lateral (Whirling)

Vibratory stresses under all operating conditions. Forced-damped response analysis will be conducted, if required

Recommendation for design/equipment/operational changes, if necessary

Comparison of vibratory stresses to acceptable limits to demonstrate compliance

Measurements

Measurement programs can include any are all of propulsion shaft torsional, axial, and lateral vibrations. Shaft torsional vibration is measured using strain gauges, and the axial and lateral vibrations are measured using non-contacting displacement transducers (proximity probes). Time domain data is collected over the full operating range of the system. In most cases, at a minimum vibration measurements are taken under the following operations:

Steady Acceleration: Idle speed to full RPM.

Free-Route at constant speeds: 10 or more equal speed increments

Hard Turns to Port and Starboard

Crash Stop

LLT uses the state-of-the-art instrumentation and software to conduct propulsion shaftline vibration measurements. The instrumentation includes digital telemetry systems, weldable strain gauges, and proximity probes. The data acquisition and analysis is done at near real time on a Lap Top PC, using the most advanced software available.

Analysis and Reporting

Preliminary results are provided on-board the vessel. This includes an assessment as to the severity of the vibration and if further testing is required. The measured vibrations are compared to the vibration standards/criteria. Criteria that are exceeded are further investigated and the potential cause and recommended action are provided. A formal Engineering report is submitted within two weeks of the completion of the tests.

COST

Fixed-price or cost plus quotes are provided.

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