CPA upgrades its crane analysis software

Casper, Phillips & Associates (CPA) has upgraded its crane analysis software.

The software suite, which is a set of programs that perform both pre- and post-processing, was developed with container cranes in mind. The pre-processing module is used to develop criteria, geometry, and loads.

Pre-processing is the creation of the mathematical model of the crane structure (defining structural beams, and load cases). Processing is when you take the math model and solve it to get the forces in each structural member (beams and columns). Post-processing is when you take the forces in each structural member and check to see if the structural members have adequate strength and resilience. This stage also includes checking overall crane stability (tipping over) and making sure that the crane doesn’t overload the dock.

In addition to container cranes, CPA has also used the software to analyse other material handling equipment, such as 500 ton (454 tonnes) plus capacity Goliath gantry cranes, offshore floating cranes, stacker cranes, electric overhead traveling (EOT) cranes, bulk ship loaders, and unloaders. The program has also been used on industrial structures and docks.

New features

CPA has introduced new features which include a new crane code EN 13001.

The programs for stress, buckling, and fatigue will automatically analyse every structural member and check every load case

CPA said the standard is being updated more regularly than the popular European crane design code from the European Materials Handling Federation (FEM). Many ports in Asia and Europe are starting to adopt EN 13001 for this reason.

Richard Phillips, mechanical engineer at CPA, said, “We can – and will – highlight the multitude of features that complete the system but more holistically it is a showcase of our design and design review services. Ports and terminal operators repeatedly note the effectiveness of the software; we’re not looking to generate sales, as such. With our software a crane structure can be analysed in two to four weeks, depending on the complexity.

“A new crane design requires a structural analysis to assure the crane meets the purchaser’s requirements as well as applicable codes and standards. Structural analysis is also required if an existing crane design is used in a new geographic region that is subject to higher wind loads or earthquake loads.”

The upgrade allows CPA to analyse a crane structure quickly. Shortening the window for the design review will cut down on the crane’s delivery time.

Buckling output

CPA has added detailed thin panel buckling output, so users can figure out which panel is over and which load case governs. Buckling will display the governing load case not only for each plate, but each panel between stiffeners.

CPA has added detailed thin panel buckling output. This picture illustrates what thin panel buckling looks like

Thin panel buckling is a localised failure of a slender plate that is part of a large beam. The detailed buckling output will automatically show the user which load case is causing the buckling issue and where the thin panel buckling occurs on the beam. This allows the user to quickly optimise their design.

Total integration

Once the pre-processing is complete, the model is loaded into SAP2000, a commercial Finite Element Analysis program. SAP2000 solves the model and will output all forces, moments, and reactions to the post-processing programs. However, SAP2000 does not support crane design codes, which led CPA to create programs that use the SAP2000 output and check the structural members to the most popular crane codes.

Phillips said: “[SAP2000] is the best analysis software for beam modelling; it has the best non-linear time history analysis routines. For this reason, we chose SAP2000 as the processing engine for our software suite.”

He said that the programmes for stress, buckling, and fatigue will automatically analyse every structural member and check every load case. This includes checking each load case for the wind angle that maximizes the stress at each structural member.

This new proprietary crane analysis software is compatible with a series of design codes, including those of FEM, AISC, BS5400, DIN 15018, CMAA 70, and EN 13001. It is compatible with Windows-based PCs.


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