diff --git a/src/AstroHelper.jl b/src/AstroHelper.jl
index c024c71..fe1e731 100644
--- a/src/AstroHelper.jl
+++ b/src/AstroHelper.jl
@@ -1,4 +1,5 @@
 module AstroHelper
+
 using LinearAlgebra
 using DataFrames
 
diff --git a/src/aeStructures.jl b/src/aeStructures.jl
index 6dc928f..79e7e89 100644
--- a/src/aeStructures.jl
+++ b/src/aeStructures.jl
@@ -27,5 +27,35 @@ struct Section
 
 end
 
-export Section
 
+function bending_moment(s::Section, Mx, My)
+    s.data.σz = (My / s.Iyy) .* s.data.x + (Mx / s.Ixx) .* s.data.y
+
+    s.data.σz
+end
+
+function shear_stress(s::Section, Vx, Vy)
+    s.data.Δq = -(Vx / s.Iyy) * s.data.A .* s.data.x - (Vy / s.Ixx) * s.data.A .* s.data.y
+
+    s.data.Δq
+end
+
+
+function shear_flow(s::Section)
+    if !("Δq" in names(s.data))
+        error("Missing Δq from Section! Run shear_stress function.")
+    end
+
+    q = s.data.Δq
+
+    s.data.q = [q[1], q[1] + q[2], q[1] + q[2] + q[3], sum(q)]
+    s.data.q
+
+end
+
+function total_shear(s::Section, qo, thickness)
+    s.data.τ = (s.q + qo) ./ thickness
+    s.data.τ
+end
+
+export Section
\ No newline at end of file
diff --git a/test/runtests.jl b/test/runtests.jl
index 75a8836..53853bd 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,6 +1,6 @@
 using Test
 
-import AstroHelper: Quaternion, Section
+import AstroHelper: Quaternion, Section,bending_moment, shear_stress, shear_flow, total_shear
 
 
 @testset "AeroHelper" begin
@@ -23,8 +23,19 @@ import AstroHelper: Quaternion, Section
 
 
     @testset "Section" begin
+    tolerance = 1e-5
+    complist(a, b) = abs(sum(a .- b)) < tolerance
     s = Section([2,1,0.5,0.5,0.75,0.75,2], [0,12,24,24,16,8,0], [0,0,0,6,7,8,9])
     @test all([s.Ixx == 126.075 s.Iyy == 571.2 s.Ixy ≈ -28.2])
     
+    s = Section([1, .5, .5, 1], [-10, 20, 20, -10], [-5, -4, 4, 5])
+    @test all([s.Ixx == 66 s.Iyy == 600 s.Ixy == 0])
+
+    @test complist(bending_moment(s, -160000, -120000), [14121.2121 5696.9696 -13696.9696 -10121.2121])
+
+    @test complist(shear_stress(s, 600, 800), [70.6061 14.2424 -34.2424 -50.6061])
+
+    @test abs(shear_flow(s)[end]) < tolerance
+
 end
 end
\ No newline at end of file