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Video 01 - FAQ Explanatory Video

Figure 01 - Compensation

Figure 02 - Coordinate System of the Cutting

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FAQ 003216 EN

25 June 2019

Andreas Niemeier Calculation RF-CUTTING-PATTERN Tensile Membrane Structures Form-Finding and Cutting Patterns

How is the flattening procedure taking compensation into account in the determination of the cutting patterns?

Answer

The flattening procedure in the RF-CUTTING-PATTERN module is an iterative process that is flattening the respective areas of cutting pattern by minimizing the distortion energy assuming an assigned material behavior.

Simplified, the method is bearing together the initial geometry in a press assuming a friction-free contact until the stresses from the flattening are in equilibrium with each other.

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As this process covers the complete mechanical system of the curved structural component, you can additionally consider the compensation directly as a applied expansion load.

Figure 01 - Compensation

Since the expansions from the compensation specification interact with the expansions from the flattening in the RF-CUTTING-PATTERN Algorithm, this type of considering compensation cannot be compared with the usual, flat scaling of uncompensated cuttings. The consideration of the complete "Cutting Mechanism" with all expansion terms could provide a very high-quality geometry.

Before the flattening itself, the integral flattening procedure defines a coordinate system (warp and weft direction) from the mean orientation of the FE elements and uses the initially defined coordinate system to describe expansion of the compensation and stiffness, independently of the respective position of the FE elements in the coordinate system orientation. Thus, the comparison shown in the video is only valid for an isotropic linear elastic membrane model.

Figure 02 - Coordinate System of the Cutting