Merge branch 'master' of github.com:robbievanleeuwen/section-properties

Author: robbievanleeuwen

docs/source/images/sections/circle_area_geometry.png

@@ -262,9 +262,9 @@ In creating this geometry consider the following:
 
 To create the nested geometry using shapely, the code would be as follows::
 
-    mat1 = Material(name="Material 1", elastic_modulus=100, poissons_ratio=0.3, yield_strength=10, color="yellow")
-    mat2 = Material(name="Material 2", elastic_modulus=100, poissons_ratio=0.3, yield_strength=10, color="orange")
-    mat3 = Material(name="Material 3", elastic_modulus=100, poissons_ratio=0.3, yield_strength=10, color="red")
+    mat1 = Material(name="Material 1", elastic_modulus=100, poissons_ratio=0.3, yield_strength=10, density=1e-6, color="yellow")
+    mat2 = Material(name="Material 2", elastic_modulus=100, poissons_ratio=0.3, yield_strength=10, density=1e-6, color="orange")
+    mat3 = Material(name="Material 3", elastic_modulus=100, poissons_ratio=0.3, yield_strength=10, density=1e-6, color="red")
 
     sq1 = sections.rectangular_section(100, 100, material=mat1).align_center()
     sq2 = sections.rectangular_section(75, 75, material=mat2).align_center()

docs/source/images/sections/circle_area_mesh.png

@@ -106,6 +106,10 @@ circular_section
 """"""""""""""""
 ..  autofunction:: sectionproperties.pre.library.primitive_sections.circular_section
 
+circular_section_by_area
+""""""""""""""""""""""""
+..  autofunction:: sectionproperties.pre.library.primitive_sections.circular_section_by_area
+
 elliptical_section
 """"""""""""""""""
 ..  autofunction:: sectionproperties.pre.library.primitive_sections.elliptical_section

docs/source/rst/advanced_geom.rst

@@ -21,6 +21,11 @@ Circular Section
 ..  autofunction:: sectionproperties.pre.library.primitive_sections.circular_section
     :noindex:
 
+Circular Section By Area
+------------------------
+..  autofunction:: sectionproperties.pre.library.primitive_sections.circular_section_by_area
+    :noindex:
+
 Elliptical Section
 ------------------
 ..  autofunction:: sectionproperties.pre.library.primitive_sections.elliptical_section

docs/source/rst/api.rst

@@ -12,6 +12,7 @@ def concrete_rectangular_section(
     n_bar: int,
     n_circle: int,
     cover: float,
+    area: float = None,
     conc_mat: pre.Material = pre.DEFAULT_MATERIAL,
     steel_mat: pre.Material = pre.DEFAULT_MATERIAL,
 ) -> geometry.CompoundGeometry:
@@ -25,6 +26,9 @@ def concrete_rectangular_section(
     :param int n_bar: Number of steel reinforcing bars
     :param int n_circle: Number of points discretising the steel reinforcing bars
     :param float cover: Side and bottom cover to the steel reinforcing bars
+    :param float area: If provided, constructs reinforcing bars based on their area
+        rather than a diameter (prevents the underestimation of steel area due to
+        circle discretision)
     :param Optional[sectionproperties.pre.pre.Material] conc_mat: Material to associate with
         the concrete
     :param Optional[sectionproperties.pre.pre.Material] steel_mat: Material to associate with
@@ -39,10 +43,12 @@ def concrete_rectangular_section(
         from sectionproperties.pre.pre import Material
 
         concrete = Material(
-            name='Concrete', elastic_modulus=30.1e3, poissons_ratio=0.2, yield_strength=32, color='lightgrey'
+            name='Concrete', elastic_modulus=30.1e3, poissons_ratio=0.2, yield_strength=32,
+            density=2.4e-6, color='lightgrey'
         )
         steel = Material(
-            name='Steel', elastic_modulus=200e3, poissons_ratio=0.3, yield_strength=500, color='grey'
+            name='Steel', elastic_modulus=200e3, poissons_ratio=0.3, yield_strength=500,
+            density=7.85e-6, color='grey'
         )
 
         geometry = concrete_rectangular_section(
@@ -72,7 +78,15 @@ def concrete_rectangular_section(
     spacing = (b - 2 * cover - dia) / (n_bar - 1)
 
     for i in range(n_bar):
-        bar = primitive_sections.circular_section(d=dia, n=n_circle, material=steel_mat)
+        if area:
+            bar = primitive_sections.circular_section_by_area(
+                area=area, n=n_circle, material=steel_mat
+            )
+        else:
+            bar = primitive_sections.circular_section(
+                d=dia, n=n_circle, material=steel_mat
+            )
+
         geom += bar.shift_section(x_offset=x_i + spacing * i, y_offset=cover + dia / 2)
 
     return geom
@@ -87,6 +101,7 @@ def concrete_tee_section(
     n_bar: int,
     n_circle: int,
     cover: float,
+    area: float = None,
     conc_mat: pre.Material = pre.DEFAULT_MATERIAL,
     steel_mat: pre.Material = pre.DEFAULT_MATERIAL,
 ) -> geometry.CompoundGeometry:
@@ -102,6 +117,9 @@ def concrete_tee_section(
     :param int n_bar: Number of steel reinforcing bars
     :param int n_circle: Number of points discretising the steel reinforcing bars
     :param float cover: Side and bottom cover to the steel reinforcing bars
+    :param float area: If provided, constructs reinforcing bars based on their area
+        rather than a diameter (prevents the underestimation of steel area due to
+        circle discretision)
     :param Optional[sectionproperties.pre.pre.Material] conc_mat: Material to associate with
         the concrete
     :param Optional[sectionproperties.pre.pre.Material] steel_mat: Material to associate with
@@ -116,10 +134,12 @@ def concrete_tee_section(
         from sectionproperties.pre.pre import Material
 
         concrete = Material(
-            name='Concrete', elastic_modulus=30.1e3, poissons_ratio=0.2, yield_strength=32, color='lightgrey'
+            name='Concrete', elastic_modulus=30.1e3, poissons_ratio=0.2, yield_strength=32,
+            density=2.4e-6, color='lightgrey'
         )
         steel = Material(
-            name='Steel', elastic_modulus=200e3, poissons_ratio=0.3, yield_strength=500, color='grey'
+            name='Steel', elastic_modulus=200e3, poissons_ratio=0.3, yield_strength=500,
+            density=7.85e-6, color='grey'
         )
 
         geometry = concrete_tee_section(
@@ -152,7 +172,15 @@ def concrete_tee_section(
     spacing = (b - 2 * cover - dia) / (n_bar - 1)
 
     for i in range(n_bar):
-        bar = primitive_sections.circular_section(d=dia, n=n_circle, material=steel_mat)
+        if area:
+            bar = primitive_sections.circular_section_by_area(
+                area=area, n=n_circle, material=steel_mat
+            )
+        else:
+            bar = primitive_sections.circular_section(
+                d=dia, n=n_circle, material=steel_mat
+            )
+
         geom += bar.shift_section(x_offset=x_i + spacing * i, y_offset=cover + dia / 2)
 
     return geom
@@ -165,6 +193,7 @@ def concrete_circular_section(
     n_bar: int,
     n_circle: int,
     cover: float,
+    area: float = None,
     conc_mat: pre.Material = pre.DEFAULT_MATERIAL,
     steel_mat: pre.Material = pre.DEFAULT_MATERIAL,
 ) -> geometry.CompoundGeometry:
@@ -178,6 +207,9 @@ def concrete_circular_section(
     :param int n_bar: Number of steel reinforcing bars
     :param int n_circle: Number of points discretising the steel reinforcing bars
     :param float cover: Side and bottom cover to the steel reinforcing bars
+    :param float area: If provided, constructs reinforcing bars based on their area
+        rather than a diameter (prevents the underestimation of steel area due to
+        circle discretision)
     :param Optional[sectionproperties.pre.pre.Material] conc_mat: Material to associate with
         the concrete
     :param Optional[sectionproperties.pre.pre.Material] steel_mat: Material to associate with
@@ -192,10 +224,12 @@ def concrete_circular_section(
         from sectionproperties.pre.pre import Material
 
         concrete = Material(
-            name='Concrete', elastic_modulus=30.1e3, poissons_ratio=0.2, yield_strength=32, color='lightgrey'
+            name='Concrete', elastic_modulus=30.1e3, poissons_ratio=0.2, yield_strength=32,
+            density=2.4e-6, color='lightgrey'
         )
         steel = Material(
-            name='Steel', elastic_modulus=200e3, poissons_ratio=0.3, yield_strength=500, color='grey'
+            name='Steel', elastic_modulus=200e3, poissons_ratio=0.3, yield_strength=500,
+            density=7.85e-6, color='grey'
         )
 
         geometry = concrete_circular_section(
@@ -225,7 +259,15 @@ def concrete_circular_section(
     d_theta = 2 * np.pi / n_bar
 
     for i in range(n_bar):
-        bar = primitive_sections.circular_section(d=dia, n=n_circle, material=steel_mat)
+        if area:
+            bar = primitive_sections.circular_section_by_area(
+                area=area, n=n_circle, material=steel_mat
+            )
+        else:
+            bar = primitive_sections.circular_section(
+                d=dia, n=n_circle, material=steel_mat
+            )
+
         geom += bar.shift_section(
             x_offset=r * np.cos(i * d_theta), y_offset=r * np.sin(i * d_theta)
         )

docs/source/rst/section_library.rst

@@ -88,6 +88,44 @@ def circular_section(
     return geometry.Geometry(circle, material)
 
 
+def circular_section_by_area(
+    area: float, n: int, material: pre.Material = pre.DEFAULT_MATERIAL
+) -> geometry.Geometry:
+    """Constructs a solid circle centered at the origin *(0, 0)* defined by its *area*,
+    using *n* points to construct the circle.
+
+    :param float area: Area of the circle
+    :param int n: Number of points discretising the circle
+    :param Optional[sectionproperties.pre.pre.Material]: Material to associate with this geometry
+
+    The following example creates a circular geometry with an area of 200 with 32 points,
+    and generates a mesh with a maximum triangular area of 5::
+
+        from sectionproperties.pre.library.primitive_sections import circular_section_by_area
+
+        geometry = circular_section_by_area(area=310, n=32)
+        geometry.create_mesh(mesh_sizes=[5])
+
+    ..  figure:: ../images/sections/circle_area_geometry.png
+        :align: center
+        :scale: 50 %
+
+        Circular section by area geometry.
+
+    ..  figure:: ../images/sections/circle_area_mesh.png
+        :align: center
+        :scale: 50 %
+
+        Mesh generated from the above geometry.
+    """
+
+    s = 2 * np.sqrt(area / n) * np.sqrt(np.tan(np.pi / n))
+    a = s / (2 * np.tan(np.pi / n))
+    d = np.sqrt(a * a + (0.5 * s) * (0.5 * s)) * 2
+
+    return circular_section(d=d, n=n, material=material)
+
+
 def elliptical_section(
     d_y: float, d_x: float, n: int, material: pre.Material = pre.DEFAULT_MATERIAL
 ) -> geometry.Geometry: