[Cleanup] Ignore positive normal stress

src/assemblers.cc

@@ -116,7 +116,11 @@ void MyAssembler<GridView, dimension>::assembleNormalStress(
   frictionalBoundary.getNormals(normals);
   for (size_t i = 0; i < traction.size(); ++i) {
     normalStress[i] = normals[i] * traction[i];
-    assert(normalStress[i] <= 0.0);
+    if (normalStress[i] > 0.0) {
+      normalStress[i] = 0.0;
+      std::cout << "Warning: Manually reducing positive normal stress to zero."
+                << std::endl;
+    }
   }
 }