Gear rating | marine reduction gear

Marine reduction gear analysis

Gear rating and marine reduction gear analysis

For marine reduction gears, sub-surface fatigue which commonly happens on large bevel gear (mn>16), is critical in gear rating. DNV so far is the only class society that has developed the calculation method and criteria to prevent such damages. DNV’s extensive marine gear experience over the decades has led to the development of the powerful tool for gear rating and marine reduction gear analysis.

The Nauticus Machinery gear package is divided into two tools - Gear Rating and Gear Faceload. With these tools, you can calculate contact stresses, scuffing and fatigue capacity and face load distribution in marine reduction gears.

Software for marine reduction gear analysis

The software covers gear rating as limited by contact stresses (pitting, spalling or case crushing), subsurface fatigue, tooth root stresses (fatigue breakage or overload breakage), and scuffing resistance
Faceload calculation combines elastic deflection of pinion and gear with other linear misalignments
Gear Rating and Gear Faceload tools share input
Efficient determination of load-carrying capacity for gear with ice class notation
Faceload tool can be used as input to gear rating tool or for verification of the tooth contact patterns by lacquer test during the sea trial
Faceload also suitable for design optimization of the helix modification
Calculations in accordance with DNV Class Guidelines 0036 (Gear rating for marine transmissions) and 0041 (ice strengthening of propulsion machinery)
Mainly based on ISO-6336 Part 1-5 (cylindrical gears), partly on ISO 10300 Part 1-3 (bevel gears) and ISO Technical Reports on Scuffing and Fatigue Damage Accumulation

Key benefits of the Gear Faceload and Gear Rating software module

DNV’s extensive know-how and know-why
Visual representation and animation of gear geometry
Graphical representation of lead modifications
Flexible report generator
Printout of the standard gear datasheet
Calculates subsurface fatigue criteria (not in ISO)
Enhanced method for root safety on bevel gears in marine applications
Support for IACS Unified Requirements for Polar/Baltic ice-class
Calculates torque loads, surface durability, tooth strength, subsurface fatigue and scuffing due to ice impacting
Clear results and good reporting interfaces
For cylindrical gear and bevel gear

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