Optimising a double sided machining for frequency within HyperFEA

[Gawain]

Hi

I'm using the grid stiffened plugin to discretely analysis a panel, and I'm trying to use HyperFEA to size the whole panel for a given frequency.

The issue I'm having is that the panel is a double sided machining and therefore the FEM will not contain the correct BAR offsets when doing the SOL 103 frequency check within HyperFEA. i.e The updated FEM is still treated as a single sided machining when doing the SOL 103 check. Therefore when I'm using HyperFEA to optimise the whole discretely modelled panel for a given frequency, then the final frequency is incorrect once I've remove the BAR offsets.

Is there anyway within the HyperFEA process, for it to ignore the BAR offsets when doing the SOL 103 frequency check?

[Brent]

Hi Gawain,

We recommend to set the stiffener component reference plane to centroid in the sizing form, options tab. When HyperSizer updates the FEM, the bar element offsets are removed. Furthermore, the FEM moments will be consistent with the grid stiffened analysis assumptions.

See the following help topic: http://hypersizer.com/help_7.3/#FE-Beams/beam-offsets.php

-Brent

[Gawain]

Hi Brent

The reference plane options are all blanked out apart from the top face mid-plane, so I unable control the reference plane of the BAR element.  This might be because I using stringer segments to discretely model a machined stiffened panel.

So is there anyway to change the reference plane of the BARs for a stringer segment?

[James]

HyperSizer manages the CBAR element reference planes for discretely-meshed stringer segments.

You can force the software to remove reference planes, effectively setting the stringer segment reference to the neutral axis. It's a backdoor data setting.

Backdoor data form: http://hypersizer.com/help_7.3/#BackdoorData/bd-00-about.php%3FTocPath%3DSoftware%2520Forms%7CBackdoor%2520Data%2520Form%7C_____1

FEM Import/Update > "Export offset for full stiffener discrete beam elements" = No.

I hope this is helpful.

-James