correct the lamina stiffness nomenclature

src/CompositeLayupModule.jl

@@ -158,18 +158,18 @@ function thickness(cl::CompositeLayup)
 end
 
 """
-    laminate_stiffnesses!(cl::CompositeLayup, A, B, C)
+    laminate_stiffnesses!(cl::CompositeLayup, A, B, D)
 
 Compute the laminate stiffnesses, membrane, extension-bending coupling, and bending.
 
-Aij coefficients represent in-plane stiffness of the laminate, the Cij
+Aij coefficients represent in-plane stiffness of the laminate, the Dij
 coefficients represent bending stiffness, the Bij represent bending-extension
 coupling.
 """
-function laminate_stiffnesses!(cl::CompositeLayup, A, B, C)
+function laminate_stiffnesses!(cl::CompositeLayup, A, B, D)
     A .= zero(eltype(A))
     B .= zero(eltype(A))
-    C .= zero(eltype(A))
+    D .= zero(eltype(A))
     Dps = deepcopy(A)
     Tbar = deepcopy(A)
     tf = QTEQTransformer(Dps)
@@ -187,10 +187,10 @@ function laminate_stiffnesses!(cl::CompositeLayup, A, B, C)
         # Compute the extension-bending coupling stiffness
         @. B += (ze^2 - zs^2)/2 * Dps
         # Compute the bending stiffness
-        @. C += (ze^3 - zs^3)/3 * Dps
+        @. D += (ze^3 - zs^3)/3 * Dps
         zs += p.thickness
     end
-    return A, B, C
+    return A, B, D
 end
 
 """

src/FEMMShellT3FFCompModule.jl

@@ -494,7 +494,7 @@ function stiffness(self::FEMMShellT3FFComp, assembler::ASS, geom0::NodalField{FF
     _nodal_triads_e! = NodalTriadsE()
     _transfmat_g_to_a! = TransfmatGToA()
     Bm, Bb, Bs, DpsBmb, DtBs = self._Bm, self._Bb, self._Bs, self._DpsBmb, self._DtBs
-    A, B, C, BT = zeros(3, 3), zeros(3, 3), zeros(3, 3), zeros(3, 3)
+    A, B, D, BT = zeros(3, 3), zeros(3, 3), zeros(3, 3), zeros(3, 3)
     H = zeros(2, 2)
     sA, sB, sC = zeros(3, 3), zeros(3, 3), zeros(3, 3)
     sH = zeros(2, 2)
@@ -509,7 +509,7 @@ function stiffness(self::FEMMShellT3FFComp, assembler::ASS, geom0::NodalField{FF
         layup = lg[1]
         eset = lg[2]
         t = thickness(layup)
-        laminate_stiffnesses!(layup, A, B, C)
+        laminate_stiffnesses!(layup, A, B, D)
         laminate_transverse_stiffness!(layup, H)
         for i in eset # Loop over elements in the layup group
             gathervalues_asmat!(geom0, ecoords, fes.conn[i]);
@@ -682,7 +682,7 @@ function inspectintegpoints(self::FEMMShellT3FFComp, geom0::NodalField{FFlt},  u
     _nodal_triads_e! = NodalTriadsE()
     _transfmat_g_to_a! = TransfmatGToA()
     Bm, Bb, Bs, DpsBmb, DtBs = self._Bm, self._Bb, self._Bs, self._DpsBmb, self._DtBs
-    A, B, C, BT = zeros(3, 3), zeros(3, 3), zeros(3, 3), zeros(3, 3)
+    A, B, D, BT = zeros(3, 3), zeros(3, 3), zeros(3, 3), zeros(3, 3)
     H = zeros(2, 2)
     sA, sB, sC = zeros(3, 3), zeros(3, 3), zeros(3, 3)
     sH = zeros(2, 2)
@@ -720,7 +720,7 @@ function inspectintegpoints(self::FEMMShellT3FFComp, geom0::NodalField{FFlt},  u
         # Look up the layup
         layup = self.layup_groups[self._layup_group_lookup[i]][1]
         t = thickness(layup)
-        laminate_stiffnesses!(layup, A, B, C)
+        laminate_stiffnesses!(layup, A, B, D)
         laminate_transverse_stiffness!(layup, H)
         gathervalues_asmat!(geom0, ecoords, fes.conn[i]);
         gathervalues_asvec!(u, edisp, fes.conn[i]);