Crack Calculator was added

StructureHelperLogics/NdmCalculations/Cracking/ICrackedLogic.cs

@@ -0,0 +1,18 @@
+using LoaderCalculator.Data.Ndms;
+using StructureHelperCommon.Models.Forces;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperLogics.NdmCalculations.Cracking
+{
+    internal interface ICrackedLogic
+    {
+        IForceTuple StartTuple { get; set; }
+        IForceTuple EndTuple { get; set; }
+        IEnumerable<INdm> NdmCollection { get; set; }
+        bool IsSectionCracked(double factor);
+    }
+}