CADEA
MareNostrum2

Services

We offer a line of specific calculation and analysis services related to the propulsion shafting static and dynamic behavior throughout the vessel lifecycle, from the shipbuilding phase to everyday operation. We also provide services for preparing a tank-heating design calculation.

All the calculations and analyses are prepared in a class review-ready form, as PDF documents, delivered by email.


Torsional vibration analysis (steady state)

Torsional vibration behavior is by far the most important aspect of any power transmission shaft line. Therefore, it is no exaggeration to say that torsional vibration is the ultimate parameter determining whether the shaft line succeedes or fails.

For new propulsion plants, carrying out a preliminary torsional vibration analysis is highly recommended to provide important insights into the vibration behavior of the future system and help select the most appropriate system components at an early stage of the design process.

The content of a typical class review-ready torsional vibration analysis is provided in the table below.


Torsional vibration analysis report
Machinery particulars
Torsional scheme
Conclusions; Notes
Calculation data
Calculation results, summary
Natural vibrations (natural frequencies, mode shapes)
Forced vibration diagrams (angular displacements, torques, and stresses), engine normal operation
Forced vibration diagrams (angular displacements, torques, and stresses), one cylinder misfiring
Transient torsional vibration diagrams (when applicable; e.g., propeller ice-milling or electric motor short-circuit)

Spectrum

Vibration spectrum


Torsional vibration analysis (transient)

Interest in propulsion plant transient torsional vibration is rising, with growing interest for the sails in iced regions.

Transient torsional vibration analyses provide invaluable insights into plant behavior during short-lived but harsh occurrences that may damage its integrity. To fulfill regulatory requirements, a number of predefined propeller-ice interactions should be simulated and evaluated.

Transient torsional vibration analyses are also important in an electric motor or electric generator plants, where short-circuit events should be taken into consideration.


Measured and Simulated

Transient response of an engine start-up


Axial vibration analysis

Axial vibrations are a frequent characteristic of long stroke, slow speed, diesel engine propulsion plants. Moreover, axial vibrations may excite the shafting torsional vibrations when a coupled vibration analysis is an appropriate approach.

The axial vibrations of medium- and high-speed plants are usually negligible.

The content of a typical class review-ready axial vibration analysis is provided in the table below.


Axial vibration analysis report
Machinery particulars
Axial scheme
Conclusions; Notes
Calculation data
Calculation results, summary
Natural vibrations (natural frequencies, mode shapes)
Forced vibration diagrams (displacements, forces, and stresses), engine normal operation
Forced vibration diagrams (displacements, forces, and stresses), one cylinder misfiring


Lateral vibration analysis

Although excessive lateral vibrations are usually generated by a large shaft line bearing spans, too-small bearing spans may be an issue, too.

The content of a typical class review-ready lateral vibration analysis is provided in the table below.


Lateral vibration analysis report
Machinery particulars
Lateral scheme
Conclusions; Notes
Calculation data
Journal bearing characteristics (horizontal and vertical planes)
Calculation results, summary
Natural vibrations (natural frequencies and mode shapes; horizontal and vertical planes)
Forced vibration diagrams (displacements and stresses; horizontal and vertical planes)
Natural frequencies for various running conditions


Shaft alignment calculation

Calculating the shaft alignment provides shaft lines bearing positions that ensure smooth operation of the shaft line system.

The shaft alignment calculation is also a prerequisite for a meaningful lateral vibration analysis.

The content of a typical class review-ready shaft alignment calculation is provided in the table below.


Shaft alignment calculation report
Machinery particulars
Notes
Calculation data
Calculation results, initial state
Calculation results, aligned state (bearing offsets and reaction forces, deflection curve, shear force, bending moment and bending stress diagrams, alignment criteria check, bearing reactions at MCR condition)
Assembly parameters and a sketch
Jack-up parameters and a sketch (when applicable)
Aftmost bearing slope-boring parameters and a sketch (when applicable)
Shaft alignment procedure


Machinery vibration analysis

Machinery vibration is a consequence of the unbalanced forces and moments that exist during machinery operations. It is frequently associated with the resiliently mounted equipment when the appropriate support elements should be selected to minimize vibration amplitudes.

In the analysis, machinery is treated as a rigid body with six degrees of freedom. The typical analysis report comprises natural frequencies and mode shapes for the six vibration modes (i.e., longitudinal, lateral, vertical, rolling, pitch, and yawing) as well as diagrams of the resulting machinery vibration amplitudes in the horizontal and vertical directions.


TVResponse

Vibration response in the frequency domain


Tank-heating design calculation

The tank-heating design calculation provides all the necessary information for heating a cargo within the contracted terms.

When applicable, the report is accompanied by drawings of the heating coil arrangement.

The content of a typical tank-heating design calculation is provided in the table below.


Tank-heating design calculation report
General data
Excerpts from the technical specification
Conclusion; Notes
Calculation data
Calculation results (heat transfer coefficient, effective coil length, boiler capacity, coil lengths, energy required for a heating cycle, power for temperature maintenance)
Required heating times for various environmental conditions
Temperature vs. heating time diagrams
Heating coil arrangement drawings (when applicable)


Temperatures

Estimated temperatures as functions of the heating duration




We not only listen to clients' requirements but also collaborate with them to find the solutions that best meet their specific needs.