onept_creep.m

Matlab中实现轮对分析的程序以及相关的程序包,可以实现火车轮轨接触关系的分析

% M-file name: onept_creep.m
% M-file type: Function file

% This function file computes the creep forces and moments acting on the left and the right
% wheels due to the interaction between wheel and rail. This calculation is valid for a single
% point contact condition between the wheel and the rail. The inputs to the function are the
% longitudinal, lateral, and spin creepages and the contact angles. The outputs are the creep
% forces and moments resolved in longitudinal, lateral, and vertical directions.

% Kalker's creep theory is used and spin creep saturation has been taken into account.

% The outputs given by this function are called by the function file 'wheelset.m'.

function [Fcx1,Fcy1,Fcz1,Mcx1,Mcy1,Mcz1,Fcx2,Fcy2,Fcz2,Mcx2,Mcy2,Mcz2]=onept_creep(etax1,etay1,etasp1,etax2,etay2,etasp2,delta1,delta2)

% Parameters used for simulation

% muN: Product of coefficient of friction between wheel and rail (mu) and the normal load on
% the axle (N)
% f11: Lateral creep coefficient (N)
% f12: Lateral/Spin creep coefficient (N-m)
% f22: Spin creep coefficient (N-m2)
% f33: Longitudinal creep coefficient (N)

% Indicating the global nature of the variables. This means that the value of the variables need % not be specified in this function file. This value is automatically obtained from the main file % 'single_wheelset.m'. 
global muN f11 f12 f22 f33; 
% Computing the creep forces and moments at the left wheel-rail contact patch 
fcpx1=-f33*etax1; fcpy1=-f11*etay1-f12*etasp1; mcpz1=f12*etay1-f22*etasp1; 
% Creep force saturation 
beta=(1/(muN))*sqrt(fcpx1^2+fcpy1^2); 
if beta<=3 
epsilon=(1/beta)*(beta-beta^2/3+beta^3/27); 
else 
epsilon=(1/beta); 
end 
Fcpx1=epsilon*fcpx1; Fcpy1=epsilon*fcpy1; Mcpz1=epsilon*mcpz1; 
% Computing the creep forces and moments at the right wheel-rail contact patch 
fcpx2=-f33*etax2; fcpy2=-f11*etay2-f12*etasp2; mcpz2=f12*etay2-f22*etasp2; 
% Creep force saturation 
beta=(1/(muN))*sqrt(fcpx2^2+fcpy2^2); 
if beta<=3 
epsilon=(1/beta)*(beta-beta^2/3+beta^3/27);
else 
epsilon=(1/beta);
end 
Fcpx2=epsilon*fcpx2; Fcpy2=epsilon*fcpy2; Mcpz2=epsilon*mcpz2; 
% The creep forces and moments calculated above are in the contact patch plane. These forces
% and moments are resolved in the longitudinal, lateral, and vertical directions in the track
% coordinate system. The variables calculated below are passed to the function 'wheelset'.

% Resolving creep forces and moments for the left wheel

Fcx1=Fcpx1;
Fcy1=Fcpy1*cos(delta1);
Fcz1=Fcpy1*sin(delta1);
Mcx1=0;
Mcy1=-Mcpz1*sin(delta1);
Mcz1=Mcpz1*cos(delta1);

% Resolving creep forces and moments for the right wheel

Fcx2=Fcpx2;
Fcy2=Fcpy2*cos(delta2);
Fcz2=-Fcpy2*sin(delta2);
Mcx2=0;
Mcy2=Mcpz2*sin(delta2);
Mcz2=Mcpz2*cos(delta2);