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Technical Papers


SAE 2002-01-1566
Overview of Carat-4, a Multi-body Simulation and Collision Modeling Program

Daniel A. Fittanto, Roland A. Ruhl and Ericka J. Southcombe from Ruhl Forensic, Inc. Dr. Heinz Burg and Jurgen Burg from IBb Informatik GmbH and Ingenieurburo Dr. B

CARAT (Computer Aided Reconstruction of Accidents in Traffic) is a Microsoft Windows based simulation program. CARAT allows for simulation of pre-collision, collision, and post-collision dynamics in a graphical environment. CARAT can model cars, trucks, trailers and tractor/semi-trailers.

CARAT-3, released in the mid-90s, is a three degree-of-freedom (3 DOF) model with three dependent DOF, and operates mathematically in a two-dimensional (2D) graphical environment. Vehicle graphics can be viewed in three dimensions (3D). CARAT-4 implements 3D multi-body models with 10 DOF for the car model, and up to 26 DOF for the truck and trailer model. CARAT is a time forward kinetic simulation, but can also be used to perform kinematic calculations forward and backwards in time. Both CARAT-3 and CARAT-4 implement a momentum-based collision algorithm. This paper introduces and briefly describes the calculation models, and input parameters for CARAT-4 relating to the sprung masses, tire model, suspension, steering and braking systems. Graphical, tabular and plot output options are described. Additionally, the RICSAC (Research Input for Computer Simulation of Automobile Collisions) tests were modeled by the CARAT collision algorithm, and the separation velocities and Delta-V's were compared with the test data, and SMAC calculations (as reported by McHenry). CARAT-4 can be used to simulate automobiles and a range of heavy truck configurations. Potential applications of the program include analyzing and visualizing the effects of vehicle design changes and accident reconstruction. Copyright 2001 Society of Automotive Engineers, Inc.



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Technical Papers

SAE 2013-01-0785
The Accuracy of Pedestrians in Estimating the Speed of a Moving Vehicle

SAE 2010-01-0046
Observed Errors in Distance Estimation

SAE 2007-01-0758
The Experimental Study of the Air Flow Produced by Road Vehicles and its Potential Destabilizing Effect on Nearby Pedestrians

SAE 2006-01-3557
Usable Models for Free and Forced Cooling of Commercial Vehicle Drum Brakes

SAE 2006-01-3556
Comparison of Established Heavy Brake Heating / Cooling Models with HVE Brake Designer in a Real Mountain Accident

RF2005-01
Commercial Vehicle Onboard Electronics - Global Positioning Systems, Engine Control Modules and Safety Systems and Devices

IMECE2004-59566
Analysis of a Common Cause Hypothesis in a Forensic Product Defect Analysis

SAE 2004-01-2717
Safety Concerns in Automatic Control of Heavy-Duty Articulated Vehicles

SAE 2003-01-3393
Numerical Methods for Evaluating ECM Data in Accident Reconstruction and Vehicle Dynamics

SAE 2003-01-3363
Development of a Dynamic Model of an Air-ride Seat for On-highway Trucks

SAE 2003-01-3419
Simulation of Intelligent Convoy with Autonomous Articulated Commercial Vehicles

SAE 2002-01-3104
Factors Affecting the Friction Coefficients Between Wooden and Plastic Pallets and the Wooden Floor Of A Van-type Semi-trailer

SAE 2002-01-1566
Overview of Carat-4, a Multi-body Simulation and Collision Modeling Program

SAE 2001-01-2755
Factors Affecting the Friction Coefficients Between Wooden Pallets and the Wooden Floor of a Van-type Semi-trailer

SAE 2000-01-3476
Fluid Load Analysis Within the Static Roll Model

RF2000-01
The Post-Kumho Exclusion of a Traffic Accident Reconstruction Expert

SAE 1999-01-3782
A Prototype Computer Based Test System to Test Commercial Vehicle Air Brake Systems: Application and Test Results

SAE 1999-01-3732
Dynamics and Roll Stability of a Loaded Class 8 Tractor-Livestock Semi-Trailer

SAE 973261
Prediction of Steady State Roll Threshold for Loaded Flat Bed Trailers - Theory and Calculation

SAE 971033
Ventilated Brake Rotor Air Flow Investigation

SAE 900106
Skidmark Signatures of ABS-Equipped Passenger Cars

SAE 880066
Combining Scene Data with Trajectory Information for Effective Accident Simulation