feat: add analysis model objects

src/property/ShellProperty.cpp

@@ -0,0 +1,26 @@
+#include "fesa/property/ShellProperty.hpp"
+
+#include <stdexcept>
+
+namespace fesa::property {
+
+ShellProperty::ShellProperty(PropertyId id, MaterialId material_id, double thickness)
+    : id_(id), material_id_(material_id), thickness_(thickness) {
+    if (thickness <= 0.0) {
+        throw std::invalid_argument("shell property thickness must be positive");
+    }
+}
+
+PropertyId ShellProperty::id() const noexcept {
+    return id_;
+}
+
+MaterialId ShellProperty::materialId() const noexcept {
+    return material_id_;
+}
+
+double ShellProperty::thickness() const noexcept {
+    return thickness_;
+}
+
+} // namespace fesa::property