Using this calculator you can visualise the shear force, bending moment and deflection of a cantilever beam when a triangular load is applied spanning distance 'a' to 'b' from the wall support.
Calculations Applied force is negative (-) in the downwards direction.
Cantilever beam with Triangular load
Cantilever beam with Triangular load
Inputs Length of beam, Distance from wall support to the zero load end, Distance from wall support to the maximum load end, Magnitude of maximum load,
Elastic Modulus, Second Moment of Inertia,
Outputs Note, self-weight loading is excluded.
Resultant force of triangular load, Span of load, Distance,
Maximum Forces and Deflection
Max Deflection
: -70.83 mm
Output Diagrams Can’t display the image because of an internal error. Our team is looking at the issue.
Beam Analysis Equations Using Macaulay's Theorem and the Double Integration Method, we can create the equations for shear force, bending moment and deflection as follows:
Shear Force i) Type 1 loading condition:
V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + F 2 c < x − a > 2 − F < x − b > 1 − F 2 c < x − b > 2 = V < x − 0 > 0 + F 2 c < x − a > 2 − F < x − b > 1 − F 2 c < x − b > 2 V(x) = -M<x-0>^{-1} + V<x-0>^{0} + \frac{F}{2c}<x-a>^{2} - F<x-b>^{1} - \frac{F}{2c}<x-b>^{2}\\= V<x-0>^{0} + \frac{F}{2c}<x-a>^{2} - F<x-b>^{1} - \frac{F}{2c}<x-b>^{2} V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + 2 c F < x − a > 2 − F < x − b > 1 − 2 c F < x − b > 2 = V < x − 0 > 0 + 2 c F < x − a > 2 − F < x − b > 1 − 2 c F < x − b > 2 ii) Type 2 loading condition:
V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + F < x − b > 1 − F 2 c < x − b > 2 + F 2 c < x − a > 2 = V < x − 0 > 0 + F < x − b > 1 − F 2 c < x − b > 2 + F 2 c < x − a > 2 V(x) = -M<x-0>^{-1} + V<x-0>^{0} + F<x-b>^{1} - \frac{F}{2c}<x-b>^{2} + \frac{F}{2c}<x-a>^{2}\\=V<x-0>^{0} + F<x-b>^{1} - \frac{F}{2c}<x-b>^{2} + \frac{F}{2c}<x-a>^{2} V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + F < x − b > 1 − 2 c F < x − b > 2 + 2 c F < x − a > 2 = V < x − 0 > 0 + F < x − b > 1 − 2 c F < x − b > 2 + 2 c F < x − a > 2 Bending Moment i) Type 1 loading condition:
M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + F 6 c < x − a > 3 − F 2 < x − b > 2 − F 6 c < x − b > 3 M(x) = -M<x-0>^0 + V<x-0>^{1} + \frac{F}{6c}<x-a>^{3} - \frac{F}{2}<x-b>^{2} -\frac{F}{6c}<x-b>^{3} M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + 6 c F < x − a > 3 − 2 F < x − b > 2 − 6 c F < x − b > 3 ii) Type 2 loading condition:
M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + F 2 < x − b > 2 − F 6 c < x − b > 3 + F 6 c < x − a > 3 M(x) = -M<x-0>^0 + V<x-0>^{1} + \frac{F}{2}<x-b>^{2} - \frac{F}{6c}<x-b>^{3} +\frac{F}{6c}<x-a>^{3} M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + 2 F < x − b > 2 − 6 c F < x − b > 3 + 6 c F < x − a > 3 Deflection i) Type 1 loading condition:
Y ( x ) = 1 E I [ − M 2 < x − 0 > 2 + V 6 < x − 0 > 3 + F 120 c < x − a > 5 − F 24 < x − b > 4 − F 120 c < x − b > 5 ] Y(x) =\frac{1}{EI}[-\frac{M}{2}<x-0>^2 + \frac{V}{6}<x-0>^{3} + \frac{F}{120c}<x-a>^{5} - \frac{F}{24}<x-b>^{4} -\frac{F}{120c}<x-b>^{5}] Y ( x ) = E I 1 [ − 2 M < x − 0 > 2 + 6 V < x − 0 > 3 + 120 c F < x − a > 5 − 24 F < x − b > 4 − 120 c F < x − b > 5 ] ii) Type 2 loading condition:
Y ( x ) = 1 E I [ − M 2 < x − 0 > 2 + V 6 < x − 0 > 3 + F 24 < x − b > 4 − F 120 c < x − b > 5 + F 120 c < x − a > 5 ] Y(x) =\frac{1}{EI}[\frac{-M}{2}<x-0>^{2} + \frac{V}{6}<x-0>^{3} + \frac{F}{24}<x-b>^{4} - \frac{F}{120c}<x-b>^{5} +\frac{F}{120c}<x-a>^{5}] Y ( x ) = E I 1 [ 2 − M < x − 0 > 2 + 6 V < x − 0 > 3 + 24 F < x − b > 4 − 120 c F < x − b > 5 + 120 c F < x − a > 5 ] Want to know how to derive the equations? Keep reading!
Derivation Step 1: Find the beam support reactions by using the equilibrium equations.
Cantilever beam with Triangular load
Cantilever beam with Triangular load
Distance formulas for Type 1
Distance formulas for Type 2
Beam support reactions (same for Type 1 and Type 2):
Σ F y = 0 V = − w where: w = 1 2 F × c \Sigma F_y = 0 \\ V = -w\\\text{where: } w = \frac{1}{2}F\times c Σ F y = 0 V = − w where: w = 2 1 F × c
Σ M 0 = 0 M = − w × d where: w = 1 2 F × c \Sigma M_0 = 0 \\ M = -w\times d\\\text{where: } w = \frac{1}{2}F\times c Σ M 0 = 0 M = − w × d where: w = 2 1 F × c
Step 2: Find the shear force and bending moment equations by using the table of Macaulay's Singularity Functions on the homepage . Because the load is not applied up to the right end of the beam, there are a few extra steps to consider: Change the FBD so that the distributed load extends all the way to the end of the beam. Make sure the resultant directly gives the original FBD. Apply Macaulay's Theorem as normal to get the and equations considering all forces along the beam Find slope, given by:
m = y 2 − y 1 x 2 − x 1 = F − 0 b − a = F c m = \dfrac{y_2 - y_1}{x_2 - x_1} = \dfrac{F-0}{b-a} = \dfrac{F}{c} m = x 2 − x 1 y 2 − y 1 = b − a F − 0 = c F Free body diagram adjusted for Macaulay's Theorem
Free body diagram adjusted for Macaulay's Theorem
Type 1 loading condition:
V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + F 2 c < x − a > 2 − F < x − b > 1 − F 2 c < x − b > 2 = V < x − 0 > 0 + F 2 c < x − a > 2 − F < x − b > 1 − F 2 c < x − b > 2 V(x) = -M<x-0>^{-1} + V<x-0>^{0} + \frac{F}{2c}<x-a>^{2} - F<x-b>^{1} - \frac{F}{2c}<x-b>^{2}\\= V<x-0>^{0} + \frac{F}{2c}<x-a>^{2} - F<x-b>^{1} - \frac{F}{2c}<x-b>^{2} V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + 2 c F < x − a > 2 − F < x − b > 1 − 2 c F < x − b > 2 = V < x − 0 > 0 + 2 c F < x − a > 2 − F < x − b > 1 − 2 c F < x − b > 2
M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + F 6 c < x − a > 3 − F 2 < x − b > 2 − F 6 c < x − b > 3 M(x) = -M<x-0>^0 + V<x-0>^{1} + \frac{F}{6c}<x-a>^{3} - \frac{F}{2}<x-b>^{2} -\frac{F}{6c}<x-b>^{3} M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + 6 c F < x − a > 3 − 2 F < x − b > 2 − 6 c F < x − b > 3 Type w loading condition:
V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + F < x − b > 1 − F 2 c < x − b > 2 + F 2 c < x − a > 2 = V < x − 0 > 0 + F < x − b > 1 − F 2 c < x − b > 2 + F 2 c < x − a > 2 V(x) = -M<x-0>^{-1} + V<x-0>^{0} + F<x-b>^{1} - \frac{F}{2c}<x-b>^{2} + \frac{F}{2c}<x-a>^{2}\\=V<x-0>^{0} + F<x-b>^{1} - \frac{F}{2c}<x-b>^{2} + \frac{F}{2c}<x-a>^{2} V ( x ) = − M < x − 0 > − 1 + V < x − 0 > 0 + F < x − b > 1 − 2 c F < x − b > 2 + 2 c F < x − a > 2 = V < x − 0 > 0 + F < x − b > 1 − 2 c F < x − b > 2 + 2 c F < x − a > 2
M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + F 2 < x − b > 2 − F 6 c < x − b > 3 + F 6 c < x − a > 3 M(x) = -M<x-0>^0 + V<x-0>^{1} + \frac{F}{2}<x-b>^{2} - \frac{F}{6c}<x-b>^{3} +\frac{F}{6c}<x-a>^{3} M ( x ) = − M < x − 0 > 0 + V < x − 0 > 1 + 2 F < x − b > 2 − 6 c F < x − b > 3 + 6 c F < x − a > 3 Step 3 : Perform the Double Integration Method to find the deflection equation.
Integrate the Bending moment equations once to get the Slope Equation.
θ ( x ) = 1 E I ∫ M ( x ) d x \theta(x) = \frac{1}{EI}\int M(x) \hspace{0.1cm} dx θ ( x ) = E I 1 ∫ M ( x ) d x i) Type 1 loading condition:
θ ( x ) = 1 E I [ − M < x − 0 > 1 + V 2 < x − 0 > 2 + F 24 c < x − a > 4 − F 6 < x − b > 3 − F 24 c < x − b > 4 + C 1 ] \\ \theta(x) = \frac{1}{EI} [-M<x-0>^1 + \frac{V}{2}<x-0>^{2} + \frac{F}{24c}<x-a>^{4} - \frac{F}{6}<x-b>^{3} -\frac{F}{24c}<x-b>^{4} +\hspace{0.1cm} C_{1}] θ ( x ) = E I 1 [ − M < x − 0 > 1 + 2 V < x − 0 > 2 + 24 c F < x − a > 4 − 6 F < x − b > 3 − 24 c F < x − b > 4 + C 1 ] ii) Type 2 loading condition:
θ ( x ) = 1 E I [ − M < x − 0 > 1 + V 2 < x − 0 > 2 + F 6 < x − b > 3 − F 24 c < x − b > 4 + F 24 c < x − a > 4 + C 1 ] \theta(x) = \frac{1}{EI} [{-M}<x-0>^{1} + \frac{V}{2}<x-0>^{2} + \frac{F}{6}<x-b>^{3} - \frac{F}{24c}<x-b>^{4} +\frac{F}{24c}<x-a>^{4} +\hspace{0.1cm} C_{1}] θ ( x ) = E I 1 [ − M < x − 0 > 1 + 2 V < x − 0 > 2 + 6 F < x − b > 3 − 24 c F < x − b > 4 + 24 c F < x − a > 4 + C 1 ] Integrate the Slope Equation to find the Deflection Equation.
Y ( x ) = 1 E I ∫ θ ( x ) d x Y(x) = \frac{1}{EI}\int \theta(x) \hspace{0.1cm} dx Y ( x ) = E I 1 ∫ θ ( x ) d x i) Type 1 loading condition:
Y ( x ) = 1 E I [ − M 2 < x − 0 > 2 + V 6 < x − 0 > 3 + F 120 c < x − a > 5 − F 24 < x − b > 4 − F 120 c < x − b > 5 + C 1 x + C 2 ] Y(x) =\frac{1}{EI}[-\frac{M}{2}<x-0>^2 + \frac{V}{6}<x-0>^{3} + \frac{F}{120c}<x-a>^{5} - \frac{F}{24}<x-b>^{4} -\frac{F}{120c}<x-b>^{5} +\hspace{0.1cm} C_{1}x +\hspace{0.1cm} C_{2}] Y ( x ) = E I 1 [ − 2 M < x − 0 > 2 + 6 V < x − 0 > 3 + 120 c F < x − a > 5 − 24 F < x − b > 4 − 120 c F < x − b > 5 + C 1 x + C 2 ] ii) Type 2 loading condition:
Y ( x ) = 1 E I [ − M 2 < x − 0 > 2 + V 6 < x − 0 > 3 + F 24 < x − b > 4 − F 120 c < x − b > 5 + F 120 c < x − a > 5 + C 1 x + C 2 ] Y(x) =\frac{1}{EI}[\frac{-M}{2}<x-0>^{2} + \frac{V}{6}<x-0>^{3} + \frac{F}{24}<x-b>^{4} - \frac{F}{120c}<x-b>^{5} +\frac{F}{120c}<x-a>^{5} +\hspace{0.1cm} C_{1}x +\hspace{0.1cm} C_{2}] Y ( x ) = E I 1 [ 2 − M < x − 0 > 2 + 6 V < x − 0 > 3 + 24 F < x − b > 4 − 120 c F < x − b > 5 + 120 c F < x − a > 5 + C 1 x + C 2 ] Apply the Boundary Conditions to find the constants and i) Type 1 loading condition:
BC 1: @ x=0, θ (x)=0 0 = 1 E I [ − M < 0 − 0 > 1 + V 2 < 0 − 0 > 2 + F 24 c < 0 − a > 4 − F 6 < 0 − b > 3 − F 24 c < x − b > 4 + C 1 ] 0 = 1 E I [ 0 + 0 + 0 + 0 + 0 + C 1 ] C 1 = 0 \text{BC 1: @ x=0, $\theta$(x)=0} \\ 0 =\frac{1}{EI} [-M<0-0>^1 + \frac{V}{2}<0-0>^{2} + \frac{F}{24c}<0-a>^{4} - \frac{F}{6}<0-b>^{3} -\frac{F}{24c}<x-b>^{4} +\hspace{0.1cm} C_{1}] \\0=\frac{1}{EI}[ 0 + 0 + 0 + 0 + 0 +C_{1}] \\ C_{1}= 0 BC 1: @ x=0, θ (x)=0 0 = E I 1 [ − M < 0 − 0 > 1 + 2 V < 0 − 0 > 2 + 24 c F < 0 − a > 4 − 6 F < 0 − b > 3 − 24 c F < x − b > 4 + C 1 ] 0 = E I 1 [ 0 + 0 + 0 + 0 + 0 + C 1 ] C 1 = 0
BC 2: @ x=0, Y(x)=0 0 = 1 E I [ − M 2 < 0 − 0 > 2 + V 6 < 0 − 0 > 3 + F 120 c < 0 − a > 5 − F 24 < 0 − b > 4 − F 120 c < 0 − b > 5 + C 2 ] 0 = 1 E I [ 0 + 0 + 0 + 0 + 0 + C 2 ] C 2 = 0 \text{BC 2: @ x=0, Y(x)=0} \\ 0 =\frac{1}{EI}[-\frac{M}{2}<0-0>^2 + \frac{V}{6}<0-0>^{3} + \frac{F}{120c}<0-a>^{5} - \frac{F}{24}<0-b>^{4} -\frac{F}{120c}<0-b>^{5} +\hspace{0.1cm} C_{2}] \\0=\frac{1}{EI}[ 0 + 0 + 0 + 0 + 0 +C_{2}] \\ C_{2}= 0 BC 2: @ x=0, Y(x)=0 0 = E I 1 [ − 2 M < 0 − 0 > 2 + 6 V < 0 − 0 > 3 + 120 c F < 0 − a > 5 − 24 F < 0 − b > 4 − 120 c F < 0 − b > 5 + C 2 ] 0 = E I 1 [ 0 + 0 + 0 + 0 + 0 + C 2 ] C 2 = 0 ii) Type 2 loading condition:
BC 1: @ x=0, θ (x)=0 0 = 1 E I [ − M < 0 − 0 > 1 + V 2 < 0 − 0 > 2 + F 24 c < 0 − a > 4 − F 6 < 0 − b > 3 − F 24 c < x − b > 4 + C 1 ] 0 = 1 E I [ 0 + 0 + 0 + 0 + 0 + C 1 ] C 1 = 0 \text{BC 1: @ x=0, $\theta$(x)=0} \\ 0 =\frac{1}{EI} [-M<0-0>^1 + \frac{V}{2}<0-0>^{2} + \frac{F}{24c}<0-a>^{4} - \frac{F}{6}<0-b>^{3} -\frac{F}{24c}<x-b>^{4} +\hspace{0.1cm} C_{1}] \\0=\frac{1}{EI}[ 0 + 0 + 0 + 0 + 0 +C_{1}] \\ C_{1}= 0 BC 1: @ x=0, θ (x)=0 0 = E I 1 [ − M < 0 − 0 > 1 + 2 V < 0 − 0 > 2 + 24 c F < 0 − a > 4 − 6 F < 0 − b > 3 − 24 c F < x − b > 4 + C 1 ] 0 = E I 1 [ 0 + 0 + 0 + 0 + 0 + C 1 ] C 1 = 0
BC 2: @ x=0, Y(x)=0 0 = 1 E I [ − M 2 < 0 − 0 > 2 + V 6 < 0 − 0 > 3 + F 24 < 0 − b > 4 − F 120 c < 0 − b > 5 + F 120 c < 0 − a > 5 + C 1 x + C 2 ] 0 = 1 E I [ 0 + 0 + 0 + 0 + 0 + C 2 ] C 2 = 0 \text{BC 2: @ x=0, Y(x)=0} \\ 0 =\frac{1}{EI}[\frac{-M}{2}<0-0>^{2} + \frac{V}{6}<0-0>^{3} + \frac{F}{24}<0-b>^{4} - \frac{F}{120c}<0-b>^{5} +\frac{F}{120c}<0-a>^{5} +\hspace{0.1cm} C_{1}x +\hspace{0.1cm} C_{2}] \\0=\frac{1}{EI}[ 0 + 0 + 0 + 0 + 0 +C_{2}] \\ C_{2}= 0 BC 2: @ x=0, Y(x)=0 0 = E I 1 [ 2 − M < 0 − 0 > 2 + 6 V < 0 − 0 > 3 + 24 F < 0 − b > 4 − 120 c F < 0 − b > 5 + 120 c F < 0 − a > 5 + C 1 x + C 2 ] 0 = E I 1 [ 0 + 0 + 0 + 0 + 0 + C 2 ] C 2 = 0 So you final Deflection equations are: i) Type 1 loading condition:
Y ( x ) = 1 E I [ − M 2 < x − 0 > 2 + V 6 < x − 0 > 3 + F 120 c < x − a > 5 − F 24 < x − b > 4 − F 120 c < x − b > 5 ] Y(x) =\frac{1}{EI}[-\frac{M}{2}<x-0>^2 + \frac{V}{6}<x-0>^{3} + \frac{F}{120c}<x-a>^{5} - \frac{F}{24}<x-b>^{4} -\frac{F}{120c}<x-b>^{5}] Y ( x ) = E I 1 [ − 2 M < x − 0 > 2 + 6 V < x − 0 > 3 + 120 c F < x − a > 5 − 24 F < x − b > 4 − 120 c F < x − b > 5 ] ii) Type 2 loading condition:
Y ( x ) = 1 E I [ − M 2 < x − 0 > 2 + V 6 < x − 0 > 3 + F 24 < x − b > 4 − F 120 c < x − b > 5 + F 120 c < x − a > 5 ] Y(x) =\frac{1}{EI}[\frac{-M}{2}<x-0>^{2} + \frac{V}{6}<x-0>^{3} + \frac{F}{24}<x-b>^{4} - \frac{F}{120c}<x-b>^{5} +\frac{F}{120c}<x-a>^{5}] Y ( x ) = E I 1 [ 2 − M < x − 0 > 2 + 6 V < x − 0 > 3 + 24 F < x − b > 4 − 120 c F < x − b > 5 + 120 c F < x − a > 5 ] You are now ready to plot the curves to determine the overall shear force, bending moment and deflection of a cantilever beam with a triangular load!