FlexuralCompressionFiberPosition FlexuralCompressionFiberPosition; //stored value for iteration
private double phiFactorDifferenceCalculation(double phi)
{
double P_nIter = phiP_n / phi;
IStrainCompatibilityAnalysisResult nominalResult = this.GetNominalMomentResult(P_nIter, FlexuralCompressionFiberPosition);
ConcreteCompressionStrengthResult result = new ConcreteCompressionStrengthResult(nominalResult, FlexuralCompressionFiberPosition, this.Section.Material.beta1);
StrengthReductionFactorFactory f = new StrengthReductionFactorFactory();
FlexuralFailureModeClassification failureMode = f.GetFlexuralFailureMode(result.epsilon_t, result.epsilon_ty);
double phiActual = f.Get_phiFlexureAndAxial(failureMode, ConfinementReinforcementType, result.epsilon_t, result.epsilon_ty);
return(phi - phiActual);
}
public ConcreteCompressionStrengthResult GetDesignMomentWithCompressionStrength(double phiP_n,
FlexuralCompressionFiberPosition FlexuralCompressionFiberPosition,
bool CapAxialForceAtMaximum = true)
{
this.phiP_n = phiP_n; //store value for iteration
this.FlexuralCompressionFiberPosition = FlexuralCompressionFiberPosition;
double P_o = GetMaximumForce();
StrengthReductionFactorFactory f = new StrengthReductionFactorFactory();
double phiAxial = f.Get_phiFlexureAndAxial(FlexuralFailureModeClassification.CompressionControlled, ConfinementReinforcementType, 0, 0);
double phiP_nMax = phiAxial * P_o;
if (phiP_n > phiP_nMax)
{
if (CapAxialForceAtMaximum == false)
{
throw new Exception("Axial forces exceeds maximum axial force.");
}
else
{
phiP_n = phiP_n;
}
}
//Estimate resistance factor to adjust from phiP_n to P_n
double phiMin = 0.65;
double phiMax = 0.9;
double ConvergenceTolerance = 0.0001;
double targetPhiFactorDifference = 0.0;
//Find P_n by guessing a phi-factor and calculating the result
double phiIterated = RootFinding.Brent(new FunctionOfOneVariable(phiFactorDifferenceCalculation), phiMax, phiMin, ConvergenceTolerance, targetPhiFactorDifference);
double P_nActual = phiP_n / phiIterated;
//Calculate final results using the estimated value of phi
IStrainCompatibilityAnalysisResult nominalResult = this.GetNominalMomentResult(P_nActual, FlexuralCompressionFiberPosition);
ConcreteCompressionStrengthResult result = new ConcreteCompressionStrengthResult(nominalResult, FlexuralCompressionFiberPosition, this.Section.Material.beta1);
FlexuralFailureModeClassification failureMode = f.GetFlexuralFailureMode(result.epsilon_t, result.epsilon_ty);
double phiFinal = f.Get_phiFlexureAndAxial(failureMode, ConfinementReinforcementType, result.epsilon_t, result.epsilon_ty);
double phiM_n = phiFinal * nominalResult.Moment;
result.phiM_n = phiM_n;
result.FlexuralFailureModeClassification = failureMode;
return(result);
}
public List <PMPair> GetPMPairs(FlexuralCompressionFiberPosition CompressionFiberPosition, int NumberOfSteps = 50, bool IncludeResistanceFactor = true)
{
List <PMPair> Pairs = new List <PMPair>();
List <SectionAnalysisResult> SectionResults = GetInteractionResults(CompressionFiberPosition, NumberOfSteps);
foreach (var thisDistibutionResult in SectionResults)
{
IStrainCompatibilityAnalysisResult nominalResult = GetResult(thisDistibutionResult);
ConcreteCompressionStrengthResult result = new ConcreteCompressionStrengthResult(nominalResult, CompressionFiberPosition, this.Section.Material.beta1);
StrengthReductionFactorFactory f = new StrengthReductionFactorFactory();
FlexuralFailureModeClassification failureMode = f.GetFlexuralFailureMode(result.epsilon_t, result.epsilon_ty);
double phi;
if (IncludeResistanceFactor == true)
{
phi = f.Get_phiFlexureAndAxial(failureMode, ConfinementReinforcementType, result.epsilon_t, result.epsilon_ty);
}
else
{
phi = 1.0;
}
double SignFactor = 1.0;
//if (CompressionFiberPosition == FlexuralCompressionFiberPosition.Bottom)
//{
// SignFactor = -1.0;
//}
double P = thisDistibutionResult.AxialForce * phi;
double M = thisDistibutionResult.Moment * phi * SignFactor;
PMPair thisPair = new PMPair(P, M);
Pairs.Add(thisPair);
}
if (IncludeResistanceFactor == true)
{
List <PMPair> TruncatedPairs = TruncateInteractionDiagram(Pairs, CompressionFiberPosition);
return(TruncatedPairs);
}
else
{
return(Pairs);
}
}