---
title: "ARMD Software – TORSION"
description: "ARMD Software: TORSION V6.2. Package for Torsional Vibration Analysis.     The torsional vibration package “TORSION V6.2” uses a finite-element based formulation for per~forming damped and undamped torsional natural frequencies, mode shapes, stability, steady-state response, and time-transient response of complete"
url: https://www.laschet.com/en/engineering/rotordynamics/armd-software-torsion/
date: 2019-12-25
modified: 2024-12-29
author: "Dr. Andreas Laschet"
type: page
lang: de-DE
---

# ARMD Software – TORSION

# ARMD Software: TORSION V6.2

## Package for Torsional Vibration Analysis

![Typical application of TORSION](https://www.laschet.com/wp-content/uploads/TORSION-10.jpg)

The torsional vibration package “**TORSION V6.2**” uses a finite-element based formulation for per~forming damped and undamped torsional natural frequencies, mode shapes, stability, steady-state response, and time-transient response of complete mechanical drive trains. **TORSION** consists of three modules: **TORNAT**, **TORHRM**, and **TORRSP** integrated by **TORSION**’s module messenger. The messenger controls the modules to provide a complete torsional vibration analysis environ~ment.

One of **TORSION**’s important advantages is that the package accepts/imports models generated with the rotor dynamics package **ROTLAT**. Thus, **TORSION** can use the **ROTLAT** models (without bearing influence).

Furthermore **TORSION** has advanced modeling features and capabilities including the mo~del~ing of multi-shaft and multi-branch systems, coupling stiff~ness and damping, gear tooth flexi~bi~li~ty, stiff~ness / mass / inertia diameter, torsional springs to ground, various types of external excitations containing harmonic parts, syn~chronous motor start-up torque (in~cluding com~plete run-up), dynamic load torques (e.g. by a recip com~pressor), user specified time varying torques, electrical faults and start-up scenarios for motor and generator, and many others.

![](https://www.laschet.com/wp-content/uploads/Example-21a-300x219.jpg)

Among the features incorporated in **TORSION** package are electrically-induced, time-varying exciting torques associated with genera~tor and induction motor operation that include:

**Generator**

- 3-phase short circuit
- Line-to-line short circuit
- False coupling short circuit

**Induction Motor**

- Start from standstill
- 3-phase short circuit at terminals
- 2-phase short circuit at terminals
- High-speed automatic reclosing

![TORSION: Time-transient response due to short circuits](https://www.laschet.com/wp-content/uploads/TORSION-06.jpg) ![TORSION: Time-transient response due to short circuits](https://www.laschet.com/wp-content/uploads/TORSION-07.jpg)

**TORSION** results include:

**NATURAL FREQUENCY, MODE SHAPES**

(Module “**TORNAT**”)

- Damped and undamped
- Growth factors and damping ratios
- Vibration mode shapes
- Critical speed map (Campbell diagrams)

![TORSION model and mode shape presentation (1st mode)](https://www.laschet.com/wp-content/uploads/Torsion-SystemModel.png)

![TORSION: Campbell diagram (interference diagram)](https://www.laschet.com/wp-content/uploads/Torsion-CriticalSpeedMap.png)

**STEADY-STATE RESPONSE**

(Module “**TORHRM**”)

- Vibratory amplitudes (displacement, velocity and acceleration)
- Dynamic torques
- Dynamic stresses
- Dynamic heat dissipation

**TIME-TRANSIENT RESPONSE**

(Module “**TORRSP**”)

- Dynamic shaft-torque time-history
- Dynamic stresses
- Fatigue life

![TORSION: Steady-state simulation "Torque vs. Speed" and time dependent simulation "Torque vs. Time"](https://www.laschet.com/wp-content/uploads/TORSION-03.jpg)

Detailed information on [**TORSIONAL VIBRATIONS including advanced engineering service**](/en/engineering/torsional-vibrations/) are presented on a special site.

*Figures and screenshots provided with kind permission of RBTS / Concepts NREC.*