NUCARS®: Recent Updates and Revisions

Release Notes 2014.3
Release Notes 2013.1
Release Notes 2012.1
Release Notes 2011.2
Release Notes 2011.1
Release Notes 2010.1
Release Notes 2009.2
Release Notes 2009.1
Release Notes 2008.1


NUCARS® Software

  • Improved Algorithms for Simulation of Link Type Suspension
    • New algorithms for all connection types except wheel/rail connections
    • Increases accuracy of calculation of angular motions
    • Involved improving the small angle calculation approximations to:
      • sinφ = φ
      • cosφ = 1 - φ² / 2
    • Previous small angle assumptions were: (as described section 1.5 of Users Manual.)
      • sinφ = φ
      • cosφ = 1
    • Has resulted in increased accuracy for simulation of suspension elements such as radial arms, swing hangers and other link type suspensions, including the roll motions
      of sideframes in 3-piece trucks such as the Swing Motion™ truck.
  • NUCARS Batch File creation tool in NUCARS®
  • Wheel/Rail Penetration Contact Model
    • Increases realism and accuracy of wheel/rail force calculations by use of multiple overlapping contact patches and a penetration algorithm
    • Reduces unstable wheel/rail force contact calculations
    • Realistic representation of conditions leading to rolling contact fatigue (RCF) and wear
    • Includes capability to vary rail profile shapes along the track
  • Animated Output of the Wheel/Rail Contact Geometry from the Penetration Model using MultiVu™
  • Beta Version of a Multibody - Track model within NUCARS®
  • Beta Version of a New TrakVu™ Track Geometry Pre-Processor Program.
    • Features an improved user interface and increased analysis capabilities based on the MultiVu™ data analysis post-processing program
  • New Connection Types
    • Type 6.8 (friction wedge model with stick-slip friction)
    • Type 6.9 (stick-slip friction wedge model with longitudinal force transmission and concave column wear surface (variable toe-in/toe-out)
  • NUCARS: Revised and improved "equilibrium" calculations
  • MULTIVU: More mathematical functions, improved graphics and output, increased batch processing capabilities.
  • Revised and updated library of wheel/rail profiles and contact geometry files
  • Updates and revisions available by download from the here.

    NUCARS® Capabilities and Features

    • Multi-body simulation tool simulates any rail vehicle on any track
      • Locomotives
      • Passenger vehicles
      • Freight vehicles
      • Articulated cars
      • Multiple cars coupled together
    • Track geometry inputs may be theoretical or actual track measurements
      • Curvature and superelevation
      • Turnout geometry
      • Track crosslevel, alignment, gauge, and profile deviations
      • External forces
    • Wheel/rail force calculation
      • Forces calculated using Kalker's non-linear creep theory, [8]
      • Measured and theoretical wheel and rail profile shapes
      • Wheel profile shapes may be specified individually for each wheel
      • Two point wheel/rail contact
      • Rail profile shapes may vary along the track
      • Coefficient of friction may vary along track and across rail/wheel surface
      • Flange back contact for guard rails, turnouts and special trackwork, [5,7,9]
      • Optional traction and braking forces
      • Optional torsionally flexible axles
      • Optional independent rotating wheels
      • Optional torsional links between axles
      • Optional drive gears on axles
    • Vehicle bodies may be flexible with up to 89 modes in each principal direction
    • Suspensions described as combinations of connection elements - on or off the principal X-Y-Z axes
      • Parallel and series springs and dampers
      • Hysteresis elements
      • Stops and gap elements
      • Friction line and surface elements, including stick/slip
      • Friction wedges with optional toe in/out (for 3-piece freight trucks)
      • Air springs can be easily simulated as combinations of standard connection elements
      • Active suspensions (such as tilting trains)
    • NUCARS® Outputs
      • All body motions, velocities and accelerations
      • Eigen-values and Eigen-vectors (from NUEIGEN)
      • Wheel/rail forces in X, Y, Z and contact patch coordinates
      • Wheel/rail contact point geometry, creepages, creep forces, and contact stresses
      • Suspension forces and motions
      • Wheel and rail wear indices on flange/gauge face and tread/railhead
      • Simulated transducers