# tensors for loading and unloading frame of cycle
    loadFieldLE = odb.steps[lastStepName].frames[0].fieldOutputs['LE']
    loadFieldS = odb.steps[lastStepName].frames[0].fieldOutputs['S']
    unloadFieldLE = odb.steps[lastStepName].frames[-1].fieldOutputs['LE']
    unloadFieldS = odb.steps[lastStepName].frames[-1].fieldOutputs['S']

    # calculate tensor mean and amplitude values
    meanLE = 0.5*(loadFieldLE+unloadFieldLE)
    ampLE = 0.5*(loadFieldLE-unloadFieldLE)
    meanS = 0.5*(loadFieldS+unloadFieldS)
    ampS = 0.5*(loadFieldS-unloadFieldS)

    #store strain amplitude, and update maxumum strain amplitude
    cycEA = []
    for v in ampLE.values:
        cycE3 = v.maxPrincipal
        cycE1 = v.minPrincipal
        if abs(cycE3) > abs(cycE1):
            cycE3abs = cycE3
        else:
            cycE3abs = cycE1
        cycEA.append(cycE3abs)
        if abs(cycE3abs) > abs(cycEAmax):
            cycEAmax = cycE3abs

    # .002 store shear strain amplitude, and update maxumum strain amplitude
    cycTau = []
    for v in ampLE.values:
        cycE3 = v.maxPrincipal
        cycE1 = v.minPrincipal
        tau = (abs(cycE3) - abs(cycE1))/2
        cycTau.append(tau)