Added Formula 5.16 from NEN-EN 1992-1-1+C2:2011: Chapter 5 - Structural Analysis

blueprints/codes/eurocode/nen_en_1992_1_1_c2_2011/chapter_5_structural_analysis/formula_5_17.py

@@ -0,0 +1,52 @@
+"""Formula 5.17 from NEN-EN 1992-1-1+C2:2011: Chapter 5 - Structural Analysis."""
+
+import math
+
+from blueprints.codes.eurocode.nen_en_1992_1_1_c2_2011 import NEN_EN_1992_1_1_C2_2011
+from blueprints.codes.formula import Formula
+from blueprints.codes.latex_formula import LatexFormula
+from blueprints.type_alias import KN, KN_M2, M
+from blueprints.validations import raise_if_less_or_equal_to_zero, raise_if_negative
+
+
+class Form5Dot17EffectiveLengthBucklingLoad(Formula):
+    """Class representing formula 5.17 for the calculation of effective length of unbraced members, in the
+    case where criteria (2) and (3) do not apply such as by variable loading, :math:`l_0`.
+    """
+
+    label = "5.17"
+    source_document = NEN_EN_1992_1_1_C2_2011
+
+    def __init__(self, ei: KN_M2, n_b: KN) -> None:
+        """[:math:`l_{0}`] Effective length for unbraced members [:math:`m`].
+
+        NEN-EN 1992-1-1+C2:2011 art.5.8.3.2(6) - Formula (5.17)
+
+        Parameters
+        ----------
+        ei : KN_M2
+            [:math:`EI`] is a representative bending stiffness [:math:`kN/m^2`].
+        n_b : KN
+            [:math:`N_{b}`] is the buckling load expressed in terms of EI (in equation (5.14) i should correspond
+            to this EI). [:math:`kN`].
+        """
+        super().__init__()
+        self.ei = ei
+        self.n_b = n_b
+
+    @staticmethod
+    def _evaluate(ei: KN_M2, n_b: KN) -> M:
+        """Evaluates the formula, for more information see the __init__ method."""
+        raise_if_negative(ei=ei, n_b=n_b)
+        raise_if_less_or_equal_to_zero(n_b=n_b)
+        return math.pi * math.sqrt(ei / n_b)
+
+    def latex(self) -> LatexFormula:
+        """Returns LatexFormula object for formula 5.17."""
+        return LatexFormula(
+            return_symbol=r"l_0",
+            result=f"{self:.3f}",
+            equation=r"\pi \cdot \sqrt{\frac{EI}{N_{b}}}",
+            numeric_equation=rf"\pi \cdot \sqrt{{\frac{{{self.ei}}}{{{self.n_b}}}}}",
+            comparison_operator_label="=",
+        )

blueprints/type_alias.py

@@ -56,6 +56,11 @@
 M4 = float
 # </editor-fold>
 
+# <editor-fold desc="COMPOUNDS">
+N_M2 = float
+KN_M2 = float
+# </editor-fold>
+
 # <editor-fold desc="TIME">
 HOURS = float
 MINUTES = float

docs/source/codes/eurocode/ec2_1992_1_1_2011/formulas.md

@@ -63,7 +63,7 @@ Total of 304 formulas present.
 | 5.14           | :heavy_check_mark: |         | Form5Dot14SlendernessRatio                                |
 | 5.15           | :heavy_check_mark: |         | Form5Dot15EffectiveLengthBraced                           |
 | 5.16           | :heavy_check_mark: |         | Form5Dot16EffectiveLengthUnbraced                         |
-| 5.17           |        :x:         |         |                                                           |
+| 5.17           | :heavy_check_mark: |         | Form5Dot17EffectiveLengthBucklingLoad                     |
 | 5.18           |        :x:         |         |                                                           |
 | 5.19           |        :x:         |         |                                                           |
 | 5.20           |        :x:         |         |                                                           |

tests/codes/eurocode/nen_en_1992_1_1_c2_2011/chapter_5_structural_analysis/test_formula_5_17.py

@@ -0,0 +1,59 @@
+"""Testing formula 5.17 of NEN-EN 1992-1-1+C2:2011."""
+
+import pytest
+
+from blueprints.codes.eurocode.nen_en_1992_1_1_c2_2011.chapter_5_structural_analysis.formula_5_17 import Form5Dot17EffectiveLengthBucklingLoad
+from blueprints.validations import LessOrEqualToZeroError, NegativeValueError
+
+
+class TestForm5Dot17EffectiveLengthBucklingLoad:
+    """Validation for formula 5.17 from NEN-EN 1992-1-1+C2:2011."""
+
+    @pytest.fixture()
+    def form_5_17(self) -> Form5Dot17EffectiveLengthBucklingLoad:
+        """Setup and teardown for test."""
+        return Form5Dot17EffectiveLengthBucklingLoad(ei=1_000_000, n_b=5)
+
+    def test_evaluation(self, form_5_17: Form5Dot17EffectiveLengthBucklingLoad) -> None:
+        """Test the evaluation of the result."""
+        # Expected result, manually calculated
+        manually_calculated_result = 1404.96  # M
+        assert form_5_17 == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
+    @pytest.mark.parametrize(
+        ("ei", "n_b"),
+        [
+            (-1_000_000, 5),
+            (1_000_000, -5),
+            (-1_000_000, -5),
+        ],
+    )
+    def test_raise_error_when_zero_pars_are_given(self, ei: float, n_b: float) -> None:
+        """Test zero values for ei, n_b."""
+        with pytest.raises(NegativeValueError):
+            Form5Dot17EffectiveLengthBucklingLoad(ei=ei, n_b=n_b)
+
+    def test_raise_error_when_negative_pars_are_given(self) -> None:
+        """Test negative values for ei, n_b."""
+        ei = 1_000_000
+        n_b = 0
+        with pytest.raises(LessOrEqualToZeroError):
+            Form5Dot17EffectiveLengthBucklingLoad(ei=ei, n_b=n_b)
+
+    @pytest.mark.parametrize(
+        ("representation", "expected"),
+        [
+            (
+                "complete",
+                r"l_0 = \pi \cdot \sqrt{\frac{EI}{N_{b}}} = \pi \cdot \sqrt{\frac{1000000}{5}} = 1404.963",
+            ),
+            ("short", r"l_0 = 1404.963"),
+        ],
+    )
+    def test_latex(self, form_5_17: Form5Dot17EffectiveLengthBucklingLoad, representation: str, expected: str) -> None:
+        """Test the latex representation of the formula."""
+        # Object to test
+        form_5_17_latex = form_5_17.latex()
+        actual = {"complete": form_5_17_latex.complete, "short": form_5_17_latex.short}
+
+        assert actual[representation] == expected, f"{representation} representation failed."