Merge pull request #847 from peternewell/brake-shoe#2

Add additional default brakeshoe CoF

Author: peternewell

Source/Documentation/Manual/physics.rst

@@ -2753,7 +2753,8 @@ Brake Shoe Force - This is the current change being implemented. The following c
 
 ``ORTSBrakeShoeType`` - this defines a number of different brake shoe types and curves. To provide a more realistic representation of the braking force the default CoF curves are 2D, ie 
 they are impacted by both the speed and Brake Shoe Force.  Typically ``ORTSBrakeShoeType`` will have one of the following keywords included - 
-``Cast_Iron`` - cast iron brake shoe, 2D as above, ``Hi_Friction_Composite`` - high friction composite shoe, 2D as above, ``User_Defined`` - is a user defined curve 
+``Cast_Iron_P6`` - older cast iron brake shoes, 2D as above, ``Cast_Iron_P10`` - newer cast iron brake shoes with increased phosphorous, 2D as above, ``Hi_Friction_Composite`` 
+- high friction composite shoe, 2D as above, ``Disc_Pads`` - brakes with disc pads, 2D as above, ``User_Defined`` - is a user defined curve 
 using the ORTSBrakeShoeFriction parameter, 1D (ie, speed only, see above section for the parameter format).
 
 ``ORTSNumberCarBrakeShoes`` - to facilitate the operation of the default 2D curves above it is necessary to configure the number of brake shoes for each car.

Source/Orts.Simulation/Simulation/RollingStocks/MSTSWagon.cs

@@ -632,7 +632,7 @@ public virtual void LoadFromWagFile(string wagFilePath)
                     NumberCarBrakeShoes = (LocoNumDrvAxles * 4) + (WagonNumAxles * 4); // Assume 4 brake shoes per axle on all wheels
                 } 
 
-                if (Simulator.Settings.VerboseConfigurationMessages && (BrakeShoeType == BrakeShoeTypes.Cast_Iron || BrakeShoeType == BrakeShoeTypes.High_Friction_Composite))
+                if (Simulator.Settings.VerboseConfigurationMessages && (BrakeShoeType != BrakeShoeTypes.User_Defined || BrakeShoeType != BrakeShoeTypes.Unknown))
                 {
                     Trace.TraceInformation("Number of Locomotive Brakeshoes set to default value of {0}", NumberCarBrakeShoes);
                 }
@@ -641,7 +641,7 @@ public virtual void LoadFromWagFile(string wagFilePath)
             {
                 NumberCarBrakeShoes = WagonNumAxles * 4; // Assume 4 brake shoes per axle
 
-                if (Simulator.Settings.VerboseConfigurationMessages && (BrakeShoeType == BrakeShoeTypes.Cast_Iron || BrakeShoeType == BrakeShoeTypes.High_Friction_Composite))
+                if (Simulator.Settings.VerboseConfigurationMessages && (BrakeShoeType != BrakeShoeTypes.User_Defined || BrakeShoeType != BrakeShoeTypes.Unknown))
                 {
                     Trace.TraceInformation("Number of Wagon Brakeshoes set to default value of {0}", NumberCarBrakeShoes);
                 }

Source/Orts.Simulation/Simulation/RollingStocks/TrainCar.cs

@@ -684,7 +684,9 @@ public enum WagonSpecialTypes
         public enum BrakeShoeTypes
         {
             Unknown,
-            Cast_Iron,
+            Cast_Iron_P6,
+            Cast_Iron_P10,
+            Disc_Pads,
             High_Friction_Composite,
             User_Defined,
         }
@@ -3236,17 +3238,26 @@ public virtual float GetBrakeShoeFrictionFactor()
                 // Formula 9 and 10 from the paper "Study of the influence of the brake shoe temperature and wheel tread on braking effectiveness" by P Ivanov1, A Khudonogov1,
                 // E Dulskiy1, N Manuilov1, A Khamnaeva1, A Korsun1, S Treskin is used for the Cast Iron and Hi Friction Composite brake shoe friction curves.
                 // https://iopscience.iop.org/article/10.1088/1742-6596/1614/1/012086/pdf
+                //
+                // These formulas are based upon the work of Karwatzki, which is described further in "Fahrdynamik des Schienenverkehrs" by Dietrich Wende 2003.
+                // Karwatzki developed a formula for brakeshoe friction that used 5 constant values k1, ..... , k5.
+                // Wende present a number of different brake shoes k values, two sets of which line up with the UIC values above.
 
-                float NewtonsTokNewtons = 0.001f;
-                float brakeShoeForcekN = (NewtonsTokNewtons * BrakeShoeForceN) / NumberCarBrakeShoes;
-
-                if (BrakeShoeType == BrakeShoeTypes.Cast_Iron)
+                if (BrakeShoeType == BrakeShoeTypes.Cast_Iron_P6)
                 {
-                    frictionfraction = 0.6f * ((1.6f * brakeShoeForcekN + 100.0f) / (8.0f * brakeShoeForcekN + 100.0f)) * ((MpS.ToKpH(AbsSpeedMpS) + 100.0f) / (5.0f * MpS.ToKpH(AbsSpeedMpS) + 100.0f));
+                    frictionfraction = KarwatzkiBrakeShoeFriction(0.024f, 62.5f, 12.5f, 100, 20);
+                }
+                else if (BrakeShoeType == BrakeShoeTypes.Cast_Iron_P10)
+                {
+                    frictionfraction = KarwatzkiBrakeShoeFriction(0.05f, 62.5f, 31.25f, 100, 20);
                 }
                 else if (BrakeShoeType == BrakeShoeTypes.High_Friction_Composite)
                 {
-                    frictionfraction = 0.44f * ((0.1f * brakeShoeForcekN + 20.0f) / (0.4f * brakeShoeForcekN + 20.0f)) * ((MpS.ToKpH(AbsSpeedMpS) + 150.0f) / (2.0f * MpS.ToKpH(AbsSpeedMpS) + 150.0f));
+                    frictionfraction = KarwatzkiBrakeShoeFriction(0.055f, 200, 50, 150, 75);
+                }
+                else if (BrakeShoeType == BrakeShoeTypes.Disc_Pads)
+                {
+                    frictionfraction = KarwatzkiBrakeShoeFriction(0.385f, -24.5f, -27.2f, 39.5f, 33);
                 }
                 else if (BrakeShoeType == BrakeShoeTypes.User_Defined)
                 {
@@ -3303,17 +3314,26 @@ public virtual float GetBrakeShoeFrictionCoefficientHuD()
                 // Formula 9 and 10 from the paper "Study of the influence of the brake shoe temperature and wheel tread on braking effectiveness" by P Ivanov1, A Khudonogov1,
                 // E Dulskiy1, N Manuilov1, A Khamnaeva1, A Korsun1, S Treskin is used for the Cast Iron and Hi Friction Composite brake shoe friction curves.
                 // https://iopscience.iop.org/article/10.1088/1742-6596/1614/1/012086/pdf
+                //
+                // These formulas are based upon the work of Karwatzki, which is described further in "Fahrdynamik des Schienenverkehrs" by Dietrich Wende 2003.
+                // Karwatzki developed a formula for brakeshoe friction that used 5 constant values k1, ..... , k5.
+                // Wende present a number of different brake shoes k values, two sets of which line up with the UIC values above.
 
-                float NewtonsTokNewtons = 0.001f;
-                float brakeShoeForcekN = NewtonsTokNewtons * BrakeShoeForceN / NumberCarBrakeShoes;
-
-                if (BrakeShoeType == BrakeShoeTypes.Cast_Iron)
+                if (BrakeShoeType == BrakeShoeTypes.Cast_Iron_P6)
                 {
-                    frictionfraction = 0.6f * ((1.6f * brakeShoeForcekN + 100.0f) / (8.0f * brakeShoeForcekN + 100.0f)) * ((MpS.ToKpH(AbsSpeedMpS) + 100.0f) / (5.0f * MpS.ToKpH(AbsSpeedMpS) + 100.0f));
+                    frictionfraction = KarwatzkiBrakeShoeFriction (0.024f, 62.5f, 12.5f, 100, 20);
+                }
+                else if (BrakeShoeType == BrakeShoeTypes.Cast_Iron_P10)
+                {
+                    frictionfraction = KarwatzkiBrakeShoeFriction(0.05f, 62.5f, 31.25f, 100, 20);
                 }
                 else if (BrakeShoeType == BrakeShoeTypes.High_Friction_Composite)
                 {
-                    frictionfraction = 0.44f * ((0.1f * brakeShoeForcekN + 20.0f) / (0.4f * brakeShoeForcekN + 20.0f)) * ((MpS.ToKpH(AbsSpeedMpS) + 150.0f) / (2.0f * MpS.ToKpH(AbsSpeedMpS) + 150.0f));
+                    frictionfraction = KarwatzkiBrakeShoeFriction(0.055f, 200, 50f, 150, 75);
+                }
+                else if (BrakeShoeType == BrakeShoeTypes.Disc_Pads)
+                {
+                    frictionfraction = KarwatzkiBrakeShoeFriction(0.385f, -24.5f, -27.2f, 39.5f, 33);
                 }
                 else if (BrakeShoeType == BrakeShoeTypes.User_Defined)
                 {
@@ -3340,6 +3360,16 @@ public virtual float GetBrakeShoeFrictionCoefficientHuD()
             }
         }
 
+        public float KarwatzkiBrakeShoeFriction ( float k1, float k2, float k3, float k4, float k5 )
+        {
+                var friction = 0.0f;
+                float NewtonsTokNewtons = 0.001f;
+                float brakeShoeForcekN = NewtonsTokNewtons * BrakeShoeForceN / NumberCarBrakeShoes;
+                friction = k1 * ((brakeShoeForcekN + k2) / (brakeShoeForcekN + k3)) * ((MpS.ToKpH(AbsSpeedMpS) + k4) / (MpS.ToKpH(AbsSpeedMpS) + k5));
+
+                return friction;
+        }
+
         public virtual void InitializeCarHeatingVariables()
         {
             MSTSLocomotive mstsLocomotive = Train.LeadLocomotive as MSTSLocomotive;