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influx
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In the bottom left, why does the BM diagram start at -4kNm rather than 4kNm? I understand that if you make a cut you yield this result but if you don't make a cut how would you know whether it starts at -4kNm or 4kNm?
Thanks
A bending moment diagram shape is a graphical representation of the variation of bending moment along the length of a structural member under an applied load. It helps engineers and designers understand the behavior of a structure and determine its strength and stability.
The shape of a bending moment diagram is calculated using the equations of static equilibrium, which state that the sum of all forces and moments acting on a body must equal zero. By analyzing the external forces and internal stresses within a structural member, the bending moment at each point can be determined and plotted on the diagram.
The shape of a bending moment diagram is affected by several factors, including the type of load applied, the type of support conditions, and the cross-sectional shape and material properties of the structural member. These factors influence the distribution of forces and moments within the member, resulting in different bending moment diagram shapes.
The shape of a bending moment diagram indicates the magnitude and direction of bending moments at different points along a structural member. It also shows the location of maximum and minimum bending moments, which are important for determining the strength and design requirements of the member. Additionally, the shape can reveal any potential areas of weakness or instability in the structure.
The three most common types of bending moment diagram shapes are rectangular, triangular, and trapezoidal. These shapes are determined by the type of load and support conditions. Rectangular bending moment diagrams are typically seen in simply supported beams with a uniformly distributed load. Triangular bending moment diagrams are often seen in cantilever beams with a point load at the end. Trapezoidal bending moment diagrams are commonly seen in beams with a combination of point and uniformly distributed loads.