Romax - Recent Threads

Powerflow and duty cycle generation

Mohit Parmar — Mon, 05 Oct 2026 02:15:21 GMT

Why does "Powerflows in file(s) do not exactly match powerflows in duty cycle" error occur?

(This Q&A has been posted by Romax Technical Support team for the benefit of our community members)

RE: Powerflow and duty cycle generation

Mohit Parmar — Mon, 05 Oct 2026 02:15:50 GMT

When generating loadcases from recorded data in Romax DT, users may encounter the error "Powerflows in file(s) do not exactly match powerflows in duty cycle."

Refer to the description below to know more about the cause of this error and how to get around it.

The error "Powerflows in file(s) do not exactly match powerflows in duty cycle" usually happens if the loadcase selected as a template has different loadcase names when compared to the powerflow names from the imported csv file.

Correct mapping process is explained with the help of an example below, observe loadcase name "1", for this "Wheel 3 - Gear-Clutch" is engaged:

csv file that would be imported:

The powerflow numbers in the excel (.csv) file are mapped to the respective name of the loadcase and therefore to the clutch engaged for that loadcase.

On generating loadcases from recorded data, you can now observe all the powerflows with "1" (1 Load case [no.]) in the csv file are mapped to "Wheel 3 - Gear-Clutch":

RE: Romax SafeNet licensing and AWS

Mohit Parmar — Wed, 30 Sep 2026 08:15:22 GMT

This post would be talking about some of the doubts users might have while setting up Romax SafeNet license on AWS (Amazon Web Services).

Setting up Romax SafeNet license on AWS (Amazon Web Services) should work, we do not expect there to be any issues or limitations.

To lock SafeNet license file we normally use - Disk ID and Ethernet Address. These should be alright for a locking code for AWS.

To know more on any special contract requirements, we would recommend reaching out to someone on the commercial side.

Romax SafeNet licensing and AWS

Mohit Parmar — Wed, 30 Sep 2026 08:14:45 GMT

Can I set up Romax SafeNet licensing with Amazon Web Services (AWS)?

(This Q&A has been posted by Romax Technical Support team for the benefit of our community members)

Bearing Internal Clearance

Pandurang Naik — Fri, 04 Sep 2026 03:45:03 GMT

Can we consider shaft/housing roughness in the calculation of internal clearance of bearing?

(This Q&A has been posted by Cadence Technical Support for the benefit of our community members)

RE: Bearing Internal Clearance

Pandurang Naik — Fri, 04 Sep 2026 03:46:14 GMT

The surface roughness of the shaft and housing bore does not directly influence the preload or clearance of the bearing. However, Romax provides a feature to calculate press fit based on the DIN7190 standard, which takes into account the surface roughness of the shaft, housing bore, and the bearing’s inner and outer raceways when determining the press fit. Changes in surface roughness will alter the effective interference or press fit. Users can apply this effective interference as their press fit value. Ultimately, the press fit is a key factor in calculating the bearing’s internal clearance.

Note- it should be noted that the surface roughness is defined as part of the Interface definition, rather than using the more general material definitions for the components

RE: A harmonic response problem considering gyroscopic effect in Romax software

Qiang Wu — Sun, 16 Aug 2026 23:04:43 GMT

Dear Bakshi,

Thank you very much for your detailed reply.

I have mastered the software operation of single-shaft analysis in Romax, using either the Single Shaft Analysis module or the General Dynamic Analysis module. A new disc modeling problem I am addressing is as follows:

Fig. 1 three kinds of discs

There are three kinds of discs: one type is a keyed disc, which is connected with a shaft by clearance fit, as shown in Fig. 1a; another type is a disc connected with shaft by interference fit, as shown in Fig. 1b; the last type is the integrated shaft-disc.

For the integrated shaft-disc, the disc can be modelled by a short beam element. For the keyed disc and the interference-fit disc, how should each type be modeled in Romax software, respectively? Which of the two disc types mentioned above corresponds to the dynamical disc module in Romax, as shown in Fig. 2?

Fig.2 the mass module

Thank you very much for taking time out of your busy schedule to look into our questions！

A harmonic response problem considering gyroscopic effect in Romax software

Qiang Wu — Wed, 29 Jul 2026 22:24:18 GMT

Dear Experts on Romax Software,

I have recently modeled a single shaft with two rigid connections, two discs and two dynamic unbalanced loads, as shown below:

The corresponding harmonic response computation yields both frequency response curves and the corresponding resonance peaks. When I ran the same simulation in a rotordynamics software from the Professor Friswell M.I (《Dynamics of rotating machines》), I found that the resonance peak amplitude of Romax is essentially the same as the result from Friswell software when the gyroscopic effect of the dynamic discs is not considered, rather than when it is taken into account. How is the gyroscopic effect of a dynamic rotor disc configured in Romax? How is the gyroscopic effect of a shaft configured in Romax?

Thank you very much for taking the time to read my question!

Gears

Pandurang Naik — Tue, 04 Aug 2026 03:48:58 GMT

Why does the film thickness result change when the surface roughness "Ra" is altered in the ISO/TR 15144 model, even though the formula (4) does not explicitly include "Ra"?

(This Q&A has been posted by Cadence Technical Support for the benefit of our community members)

RE: Gears

Pandurang Naik — Tue, 04 Aug 2026 03:49:26 GMT

The film thickness in the ISO/TR 15144 model is influenced by several factors, even if the formula does not explicitly include surface roughness "Ra". The roughness factor affects the mean coefficient of friction, which in turn impacts the contact temperature θB,Y. Changes in contact temperature affect various parameters in the equation, such as the oil viscosity and pressure-viscosity coefficient. These parameters are part of the material parameter (Gm), local velocity parameter (Uy), and sliding parameter (Sgfy) in Equation (4). As these parameters vary with temperature, the calculated oil film thickness changes as a result. Please see ISO 15144 section 12 to 14 for more detailed explanation.

RE: A harmonic response problem considering gyroscopic effect in Romax software

Vaishali Bakshi — Fri, 31 Jul 2026 01:54:30 GMT

Hello Qiang Wu,

Thank you for contacting us! I believe you are looking for single shaft dynamic analysis. Romax Spectrum provides below analysis options for achieving the same.

If you need more information on them, kindly reach out the support portal.

RE: Shaft Nodes

Vaishali Bakshi — Mon, 27 Jul 2026 22:13:41 GMT

When components such as bearings are placed, nodes are created accordingly. However, additional nodes are automatically generated along the shaft. Node generation along a shaft is governed by the Timoshenko beam theory, which requires dividing long shaft sections for accurate static analysis. The 'Max length to diameter ratio for parallel section' setting (under Analysis settings) controls how many nodes are created. Lowering this ratio increases node count, while raising it decreases nodes. Disabling this setting stops extra node generation, but keeping it enabled is recommended for accuracy.

Shaft Nodes

Vaishali Bakshi — Mon, 27 Jul 2026 22:13:16 GMT

How Nodes are Generated on Shafts in RomaxDT?

(This Q&A has been posted by Cadence Technical Support for the benefit of our community members)

Safety Factor

Pandurang Naik — Tue, 14 Jul 2026 05:01:10 GMT

What is the difference between duty cycle safety factor and load case safety factor of a gear?

(This Q&A has been posted by Cadence Technical Support for the benefit of our community members)

RE: Safety Factor

Pandurang Naik — Tue, 14 Jul 2026 05:01:29 GMT

Load case safety factor is calculated by considering permissible (allowable) stress and actual stress. Load case safety factor is = Permissible stress / Actual stress. Duty cycle safety factor is calculated by iterative method.

Romax ensures that the total damage from all load cases equals 100% by applying an iterative method that uses a scaling factor. This scaling factor is referred to as the duty cycle safety factor. Please refer ISO 6336-6 section 5.4. If the combined damage from all load cases exceeds 100%, Romax applies a scaling factor less than 1 to reduce the total damage to exactly 100%. The specific scaling factor at which the sum of damages equals 100% is defined as the duty cycle safety factor.

RE: Mean finished profile shift for splines

Mohit Parmar — Fri, 10 Jul 2026 07:30:29 GMT

The "Mean finished profile shift" is given in units of " mm ", it is due to -

Mean finished profile shift = profile shift coefficient × normal module

Spline Coupling Properties > Design tab > "Mean finished profile shift:":

Mean finished profile shift for splines

Mohit Parmar — Fri, 10 Jul 2026 07:28:03 GMT

What is the mean finished profile shift for splines?

(This Q&A has been posted by Romax Technical Support team for the benefit of our community members)

Effect of Planet Pin Interference Fit on Tooth Load Distribution

shuang mu — Wed, 08 Jul 2026 09:22:52 GMT

How should the interference fit between the planet carrier and the planet pins be defined? Will the fit between the pins and the corresponding bores affect the tooth flank load distribution per unit face width?

RE: Effect of Planet Pin Interference Fit on Tooth Load Distribution

shuang mu — Thu, 09 Jul 2026 20:38:46 GMT

Thank you for taking the time to reply. I appreciate your help, and I will try this approach next.

RE: Effect of Planet Pin Interference Fit on Tooth Load Distribution

Vaishali Bakshi — Thu, 09 Jul 2026 04:29:43 GMT

Hello Shuang,

Thank you for reaching out us.

There is no direct option to specify this kind of fit however, you should be able to try modelling this clearance/interference using a clearance bearings in between these connections.

RE: Bearing forces

Pandurang Naik — Tue, 30 Jun 2026 01:27:06 GMT

A tapered roller bearing is primarily designed to support axial (thrust) loads. However, when a radial load is applied to the bearing, the unique contact angle of the rollers causes a portion of that radial load to be transformed into an axial load. As a result, users may observe additional axial load in the system beyond any directly applied axial force. The relationship can be expressed as:

Axial Load = Radial Load × tan(contact angle)

Bearing forces

Pandurang Naik — Tue, 30 Jun 2026 01:26:38 GMT

Why does a tapered roller bearing experience additional axial load?

(This Q&A has been posted by Cadence Technical Support for the benefit of our community members)

Advanced tooth stiffness for micro-geometry and bending results

Mohit Parmar — Tue, 23 Jun 2026 06:38:43 GMT

What happens to bending results when the advanced tooth stiffness is selected for micro-geometry analysis with K-Hbeta set as calculated?

(This Q&A has been posted by Romax Technical Support team for the benefit of our community members)

RE: Advanced tooth stiffness for micro-geometry and bending results

Mohit Parmar — Tue, 23 Jun 2026 06:42:29 GMT

Selecting the settings:

1. Advanced tooth stiffness:

2. K-Hbeta set as calculated:

ISO gear rating bending stress -

When K-Hbeta is set as calculated, Romax takes - system deflections, misalignment and tooth contact from micro geometry analysis into account to calculate the K-Hbeta.

K-Hbeta influences K-Fbeta (face load factor for tooth root stress). Reference - ISO 6336-1:2019(E) > and equation (71). Hence the bending safety factors would be affected by the advanced tooth stiffness model (reference - ISO 6336-3:2019(E) > and equations 1, 2 and 3).

FEA-based root stress analysis (Micro-geometry results > Root stress analysis…) -

Load lines from micro-geometry analysis are feed as an input to the root stress analysis. So, the bending results would be influenced by the advanced tooth stiffness model for micro geometry analysis.

Gear

Pandurang Naik — Wed, 17 Jun 2026 01:12:02 GMT

Can we Change Center Distance of Detailed Gear in RomaxDT?

(This Q&A has been posted by Cadence Technical Support for the benefit of our community members)