Update app.py

app.py

@@ -7,7 +7,7 @@ Single-file Streamlit app with:
 - Material database (selectable)
 - UG-27 shell thickness (circumferential & longitudinal checks)
 - UG-32 head thickness (ellipsoidal / torispherical / hemispherical)
-- Simplified UG-37-style nozzle reinforcement area method (approx)
+- Improved UG-37-style nozzle reinforcement area method (conservative approx)
 - PWHT recommendation (simplified, UCS-56 style)
 - Impact test (Design MDMT vs Rated MDMT) approximation (UCS-66 style approximation)
 - MAWP calculation from thickness
@@ -29,7 +29,7 @@ import pandas as pd
 import streamlit as st
 
 # Module metadata
-__version__ = "0.1.0"
+__version__ = "0.1.1"  # bumped for nozzle + edition + E updates
 
 # ---------------------------
 # Constants
@@ -37,7 +37,7 @@ __version__ = "0.1.0"
 ATM_PRESSURE_PSI = 14.7  # used only for context
 PIPE_THICKNESS_REDUCTION = 0.125  # 12.5% reduction for pipe grades
 DEFAULT_CORROSION_ALLOWANCE_IN = 0.125
-SUPPORTED_ASME_EDITIONS = ["2019", "2021", "custom"]
+SUPPORTED_ASME_EDITIONS = ["2019", "2021", "2025", "custom"]  # added 2025
 
 # Units formatting
 INCH_DECIMALS = 4
@@ -339,64 +339,84 @@ def calculate_head_thickness(P: float, D: float, S: float, E: float, head_type:
     }
 
 
-def calculate_nozzle_reinforcement(d_opening: float, t_shell_required: float, t_nozzle: float, t_pad: float, pad_width: float, material_grade: Optional[str] = None) -> Dict[str, Any]:
+def calculate_nozzle_reinforcement(
+    d_opening: float,
+    t_shell_required: float,
+    t_nozzle: float,
+    t_pad: float,
+    pad_width: float,
+    material_grade: Optional[str] = None,
+    shell_local_extra_thickness: float = 0.0,
+    weld_throat: float = 0.0,
+    weld_efficiency: float = 0.7,
+) -> Dict[str, Any]:
     """
-    Simplified UG-37 area method approximation.
-    - A_required = d_opening * t_shell_required
-    - A_nozzle approximated as t_nozzle * height (height approximated)
-    - A_pad = t_pad * pad_width
-    - A_shell conservative assumed zero (unless pad provides)
-    ASSUMPTION: This is conservative and simplified; real UG-37 includes integration over reinforcement area and weld contributions.
+    Improved simplified UG-37 area method approximation.
+
+    Method (conservative approximations):
+    - Required area: A_req = d_opening * t_shell_required
+    - Nozzle contribution: A_nozzle = pi * d_opening * t_nozzle  (cylindrical projection)
+      # APPROXIMATION: Using circumference*thickness as projected reinforcement area.
+    - Pad contribution: A_pad = pad_width * t_pad * 2 (count both faces as conservative rectangular pads)
+    - Shell local extra thickness contribution: A_shell_local = pi * d_opening * shell_local_extra_thickness
+    - Weld contribution: A_weld = weld_throat * pi * d_opening * weld_efficiency
+    - For pipe grades (SA-106B, SA-53B-ERW, SA-312-*) apply 12.5% thickness reduction to nozzle/pad/weld contributions.
+    - Assumptions and limitations are returned in 'assumptions' and should be reviewed by an engineer.
     """
-    if d_opening <= 0 or t_shell_required <= 0 or t_nozzle <= 0:
-        raise ValueError("Nozzle dimensions must be positive")
+    # Input validation
+    if d_opening <= 0:
+        raise ValueError("Nozzle opening diameter must be positive.")
+    if t_shell_required <= 0:
+        raise ValueError("Shell required thickness must be positive.")
+    if t_nozzle <= 0:
+        raise ValueError("Nozzle wall thickness must be positive.")
+
+    A_required = d_opening * t_shell_required  # projection length * thickness
+
+    # Nozzle cylindrical contribution (projection)
+    A_nozzle = math.pi * d_opening * t_nozzle  # circumference * thickness (approx)
+    # Pad contribution: two faces conservative rectangular pad
+    A_pad = pad_width * t_pad * 2.0 if (t_pad and pad_width) else 0.0
+    # Shell local extra thickness contribution (if user provides local reinforcement)
+    A_shell_local = math.pi * d_opening * shell_local_extra_thickness if shell_local_extra_thickness else 0.0
+    # Weld contribution
+    A_weld = weld_throat * math.pi * d_opening * weld_efficiency if weld_throat and weld_efficiency else 0.0
 
-    A_required = d_opening * t_shell_required
-
-    # Approximate nozzle contribution: height limited to 2.5 * smaller thickness
-    height_limit = min(2.5 * t_shell_required, 2.5 * t_nozzle)
-    A_nozzle = t_nozzle * height_limit
-
-    # Pad contribution
-    A_pad = t_pad * pad_width if (t_pad and pad_width) else 0.0
-
-    # Shell area conservative: we count none (ASSUMPTION: conservative)
-    A_shell = 0.0
-
-    # Apply pipe grade thickness reduction for nozzle if material_grade indicates pipe
     reduction_info = ""
+    # check pipe grade
     if material_grade:
-        # find if given material is in data and pipe grade
         for cat in MATERIALS:
             mg = MATERIALS[cat].get(material_grade)
             if mg:
                 if mg.get("is_pipe_grade"):
-                    # reduce nozzle effective thickness for reinforcement calc
-                    effective_nozzle_t = t_nozzle * (1.0 - PIPE_THICKNESS_REDUCTION)
-                    # recalc A_nozzle conservatively with reduced t
-                    height_limit2 = min(2.5 * t_shell_required, 2.5 * effective_nozzle_t)
-                    A_nozzle = effective_nozzle_t * height_limit2
-                    reduction_info = f"Applied {PIPE_THICKNESS_REDUCTION*100:.1f}% pipe thickness reduction to nozzle (effective nozzle thickness = {effective_nozzle_t:.4f})."
+                    # apply reduction to contributions that rely on nominal thickness (nozzle, pad, weld)
+                    A_nozzle = A_nozzle * (1.0 - PIPE_THICKNESS_REDUCTION)
+                    A_pad = A_pad * (1.0 - PIPE_THICKNESS_REDUCTION)
+                    A_weld = A_weld * (1.0 - PIPE_THICKNESS_REDUCTION)
+                    reduction_info = f"Applied {PIPE_THICKNESS_REDUCTION*100:.1f}% pipe thickness reduction to nozzle/pad/weld contributions."
                 break
 
-    A_available = A_shell + A_nozzle + A_pad
+    A_available = A_shell_local + A_nozzle + A_pad + A_weld
+
     adequate = A_available >= A_required
     safety_factor = (A_available / A_required) if A_required > 0 else float("inf")
 
     assumptions = [
-        "A_shell conservative assumed zero (no excess shell area counted).",
-        "Nozzle area approximated with a limited height = min(2.5*t_shell, 2.5*t_nozzle).",
-        "Pad area = pad_thickness * pad_width (rectangular assumption).",
-        "Real UG-37 requires geometric reinforcement calculations; this is a simplified conservative estimate.",
+        "# ASSUMPTION: Using projection-area approximations (circumference*thickness) for nozzle contribution.",
+        "# APPROXIMATION: Pad is modeled as rectangular and both faces are counted for conservatism.",
+        "# ASSUMPTION: Shell local extra thickness is approximated as circumference * extra_thickness.",
+        "# ASSUMPTION: Weld contribution approximated as weld_throat * circumference * efficiency.",
+        "Real UG-37 uses more exact geometric projections and weld strength contribution; this is conservative and simplified.",
     ]
     if reduction_info:
         assumptions.append(reduction_info)
 
     return {
         "area_required": float(A_required),
-        "area_shell": float(A_shell),
+        "area_shell_local": float(A_shell_local),
         "area_nozzle": float(A_nozzle),
         "area_pad": float(A_pad),
+        "area_weld": float(A_weld),
         "area_available_total": float(A_available),
         "reinforcement_adequate": bool(adequate),
         "safety_factor": float(safety_factor),
@@ -442,14 +462,10 @@ def _approximate_rated_mdmt(material_group: str, thickness_in_in: float) -> floa
     """
     APPROXIMATION: Provide a conservative approximate rated MDMT based on material group and thickness.
     This is NOT the full UCS-66 lookup. Use as a placeholder to compare with Design MDMT.
-    We define a simple table for P1 and P8:
-    - For P1 (carbon): thicker -> higher (warmer) rated MDMT threshold (conservative)
-    - For P8 (stainless): very low rated MDMT (stainless generally exempt)
-    Returns MDMT in °F.
+    We define a simple table for P1 and P8 (°F).
     """
     if material_group == "P8":
-        return -325.0  # effectively exempt in many cases (very low)
-    # P1 conservative regression-like mapping (values illustrative)
+        return -325.0
     if thickness_in_in <= 0.5:
         return 60.0
     if thickness_in_in <= 1.0:
@@ -559,6 +575,9 @@ def init_session_state_defaults():
         "use_reinforcing_pad": False,
         "pad_thickness": 0.25,
         "pad_width": 8.0,
+        "shell_local_extra_thickness": 0.0,
+        "weld_throat": 0.1,
+        "weld_efficiency": 0.7,
         "calc_atm_shell": False,
         "asme_edition": SUPPORTED_ASME_EDITIONS[0],
     }
@@ -627,8 +646,6 @@ def run_calculations(inputs: Dict[str, Any]) -> Dict[str, Any]:
     # Optionally compute atmospheric shell
     atm_shell = None
     if inputs.get("calc_atm_shell"):
-        # For atmospheric only, P = 0 -> thickness tends to 0. Use minimal thickness assumption.
-        # ASSUMPTION: Provide thickness for vacuum containment? Here we just return a message.
         atm_shell = {"note": "Atmospheric shell check requested: with P=0 this calculation is geometry-specific. Provide loading (wind, vacuum) for meaningful thickness check."}
 
     # Head thickness
@@ -636,12 +653,17 @@ def run_calculations(inputs: Dict[str, Any]) -> Dict[str, Any]:
     head_required = head["required_thickness"]
     total_head = head_required + ca
 
-    # Nozzle reinforcement
+    # Nozzle reinforcement (improved)
     nozzle = calculate_nozzle_reinforcement(
-        inputs["nozzle_opening_diameter"], total_shell, inputs["nozzle_wall_thickness"],
+        inputs["nozzle_opening_diameter"],
+        total_shell,
+        inputs["nozzle_wall_thickness"],
         inputs["pad_thickness"] if inputs["use_reinforcing_pad"] else 0.0,
         inputs["pad_width"] if inputs["use_reinforcing_pad"] else 0.0,
         mat_grade if mat_cat != "User Defined" else None,
+        shell_local_extra_thickness=inputs.get("shell_local_extra_thickness", 0.0),
+        weld_throat=inputs.get("weld_throat", 0.0),
+        weld_efficiency=inputs.get("weld_efficiency", 0.7),
     )
 
     # For pipe grades, mention 12.5% reduction in shell effective thickness for reinforcement checks
@@ -652,10 +674,7 @@ def run_calculations(inputs: Dict[str, Any]) -> Dict[str, Any]:
         reduced_shell_effective = total_shell
 
     # PWHT
-    # thickness for pwht in inches: if units SI, convert mm to inches (we assume inside_diameter units but thickness returned in same length units)
-    # ASSUMPTION: inputs thickness are in inches when unit_system == USC, mm when SI. For PWHT we need inches.
     if unit_system == "SI":
-        # convert mm to inches: assume thickness in mm -> mm / 25.4
         thickness_in_in = total_shell / 25.4
     else:
         thickness_in_in = total_shell
@@ -705,7 +724,7 @@ def main():
     st.session_state["unit_system"] = unit_system
 
     # ASME edition placeholder
-    st.session_state["asme_edition"] = st.sidebar.selectbox("ASME Section VIII Edition", SUPPORTED_ASME_EDITIONS, index=0)
+    st.session_state["asme_edition"] = st.sidebar.selectbox("ASME Section VIII Edition", SUPPORTED_ASME_EDITIONS, index=SUPPORTED_ASME_EDITIONS.index(st.session_state.get("asme_edition", SUPPORTED_ASME_EDITIONS[0])))
 
     # Basic design
     pressure_label = "Design Pressure (psi)" if unit_system == "USC" else "Design Pressure (bar)"
@@ -722,7 +741,8 @@ def main():
     st.sidebar.markdown("---")
     st.session_state["inside_diameter"] = st.sidebar.number_input(length_label, value=float(st.session_state["inside_diameter"]))
     st.session_state["head_type"] = st.sidebar.selectbox("Head Type", ["ellipsoidal", "torispherical", "hemispherical"], index=0 if st.session_state["head_type"] == "ellipsoidal" else 0)
-    st.session_state["joint_efficiency"] = st.sidebar.selectbox("Joint Efficiency (E)", [1.0, 0.95, 0.9, 0.85], index=0)
+    # Added E = 0.7 option as requested
+    st.session_state["joint_efficiency"] = st.sidebar.selectbox("Joint Efficiency (E)", [1.0, 0.95, 0.9, 0.85, 0.7], index=[1.0,0.95,0.9,0.85,0.7].index(st.session_state.get("joint_efficiency", 1.0)))
 
     st.sidebar.markdown("---")
     st.session_state["material_category"] = st.sidebar.selectbox("Material Category", ["Carbon Steel", "Stainless Steel", "User Defined"], index=0)
@@ -734,7 +754,6 @@ def main():
         st.session_state["user_defined_ce"] = st.sidebar.number_input("User-defined carbon equivalent (if known)", value=0.30)
     else:
         grades = list(MATERIALS[st.session_state["material_category"]].keys())
-        # select current grade if available
         try:
             idx = grades.index(st.session_state["material_grade"])
         except Exception:
@@ -750,6 +769,12 @@ def main():
         st.session_state["pad_thickness"] = st.sidebar.number_input("Pad Thickness (same unit)", value=float(st.session_state["pad_thickness"]))
         st.session_state["pad_width"] = st.sidebar.number_input("Pad Width (same unit)", value=float(st.session_state["pad_width"]))
 
+    # New inputs for improved nozzle reinforcement
+    st.sidebar.markdown("---")
+    st.session_state["shell_local_extra_thickness"] = st.sidebar.number_input("Local shell extra thickness (for reinforcement) (same unit)", value=float(st.session_state.get("shell_local_extra_thickness", 0.0)))
+    st.session_state["weld_throat"] = st.sidebar.number_input("Effective weld throat (same unit) for weld contribution", value=float(st.session_state.get("weld_throat", 0.1)))
+    st.session_state["weld_efficiency"] = st.sidebar.slider("Weld efficiency factor", min_value=0.0, max_value=1.0, value=float(st.session_state.get("weld_efficiency", 0.7)), step=0.05)
+
     st.sidebar.markdown("---")
     st.session_state["calc_atm_shell"] = st.sidebar.checkbox("Also calculate shell at atmospheric pressure", value=st.session_state["calc_atm_shell"])
 
@@ -782,6 +807,9 @@ def main():
         "use_reinforcing_pad": bool(st.session_state["use_reinforcing_pad"]),
         "pad_thickness": float(st.session_state.get("pad_thickness", 0.0)),
         "pad_width": float(st.session_state.get("pad_width", 0.0)),
+        "shell_local_extra_thickness": float(st.session_state.get("shell_local_extra_thickness", 0.0)),
+        "weld_throat": float(st.session_state.get("weld_throat", 0.1)),
+        "weld_efficiency": float(st.session_state.get("weld_efficiency", 0.7)),
         "calc_atm_shell": bool(st.session_state.get("calc_atm_shell", False)),
     }
 
@@ -823,7 +851,6 @@ def main():
 
             with st.expander("Show step-by-step shell calculations"):
                 st.code(f"Inputs: P={inputs['design_pressure']}, R={inputs['inside_diameter']/2.0}, S={get_allowable_stress(inputs['material_category'], inputs['material_grade'], inputs['design_temperature'], 'USC' if unit_system=='USC' else 'SI')[0]}, E={inputs['joint_efficiency']}")
-                # Show computed values numerically
                 st.write(shell)
         else:
             st.info("Press **Calculate** to run shell thickness calculations.")
@@ -843,23 +870,28 @@ def main():
             st.info("Press **Calculate** to run head thickness calculations.")
 
     with tab3:
-        st.header("Nozzle Reinforcement (UG-37 approx)")
+        st.header("Nozzle Reinforcement (UG-37 approx - improved)")
+        st.info("Provide nozzle geometry inputs below. The method is a conservative projection-area approximation; see assumptions in the result.")
         if results:
             nozzle = results["nozzle"]
             units_len = "in" if unit_system == "USC" else "mm"
             st.write("Assumptions:")
             for a in nozzle["assumptions"]:
                 st.write("-", a)
-            st.write("Required area:", f"{format_value(nozzle['area_required'], units_len)} {units_len}^2")
-            st.write("Available area:", f"{format_value(nozzle['area_available_total'], units_len)} {units_len}^2")
+            st.write("Required area (A_required = d_opening * t_shell):", f"{format_value(nozzle['area_required'], units_len)} {units_len}^2")
+            st.write("Shell local contribution (A_shell_local):", f"{format_value(nozzle['area_shell_local'], units_len)} {units_len}^2")
+            st.write("Nozzle contribution (A_nozzle = pi*d*t_nozzle):", f"{format_value(nozzle['area_nozzle'], units_len)} {units_len}^2")
+            st.write("Pad contribution (A_pad):", f"{format_value(nozzle['area_pad'], units_len)} {units_len}^2")
+            st.write("Weld contribution (A_weld):", f"{format_value(nozzle['area_weld'], units_len)} {units_len}^2")
+            st.write("Total available area:", f"{format_value(nozzle['area_available_total'], units_len)} {units_len}^2")
             if nozzle["reinforcement_adequate"]:
                 st.success(f"Reinforcement adequate (SF = {nozzle['safety_factor']:.2f})")
             else:
                 st.error(f"Reinforcement inadequate (SF = {nozzle['safety_factor']:.2f})")
-            with st.expander("Show step-by-step nozzle calculation"):
+            with st.expander("Show step-by-step nozzle calculation (raw values)"):
                 st.write(nozzle)
         else:
-            st.info("Press **Calculate** to run nozzle reinforcement calculations.")
+            st.info("Enter inputs and press **Calculate** to run nozzle reinforcement check.")
 
     with tab4:
         st.header("PWHT & Impact Test")
@@ -880,7 +912,6 @@ def main():
                 st.write("Suggested hold time:", pwht["hold_time"])
 
             st.subheader("Impact Test (MDMT check)")
-            # show rated and design MDMT
             rated = impact["rated_mdmt"]
             design = impact["design_mdmt"]
             if unit_system == "SI":