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Displacement/Deflection Results in S3D

Display the single-member displacement values of each member of your structure. Values for displacement are shown at the starting and ending nodes of each member. Both distance and rotational displacement values can be turned on and off with the checkboxes. The values are separated into component global X, Y, and Z values (or sum for distance displacement).

Note, as is with the other display options, what is shown depends on the Load Combination/Envelope that is chosen in the dropdown on the left-hand side. The displacement labels can be dragged to improve clarity. You can reset the position of the labels by rotating or dragging the structure.

For example, with Displacement results turned on, the wireframe will always show the displaced shape of the model. You can toggle on and off any combination of displacement results as shown:

Another screenshot:

Clicking an individual member will allow you to view the starting and ending displacement values for that member whilst hiding all others. To reshow the other shear force diagrams, reclick the Shear button on the left navigation menu.

L/Deflection Results

This common ratio helps give users a quick ratio to use for deflection limits. It’s important to understand how the software calculates these values so the engineer can interpret the results correctly. This result is often expressed as L/xx. If the value, xx, is below a certain criterion (for example 250) it is considered to have failed that criteria. For more accurate analysis and checks, SkyCiv performs two deflection/span calculations:

Span via Method 1: For continuous members, it assumes each node/connection along the member acts as a restraint or brace.
Span via Method 2: For continuous members, the span is taken over the entire length of the member regardless of the nodes/connections along the member.

For both methods, SkyCiv calculates the denominator (the xx value) of this result by dividing the member’s length by the member’s relative deflection. The relative member deflection is the deflection from the line between the ends of the member’s deflected shape.

By utilizing both methods, SkyCiv can identify and correctly calculate governing span ratios in different scenarios. For example:

Example 1: Member 30 has support (via a connected member) at the midpoint, so span 1 is more suitable and governs:

Example 2: Member 1 has connected members, but not offering any restraint. So span 2 is more suitable and governs:

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