Metal Sheet Optimization with FEA | Fixing Enclosure Failure

metal sheet enclosure

 A sample model of the metal sheet enclosure

Over the past years, cloud-based Computer Aided Engineering (CAE) has become an important tool in the product development cycle and is being used extensively in many industries like Automotive, Aerospace, HVAC, Manufacturing, Electronics and Energy. It not only provides a fast and cost-efficient method to test existing designs, but also to optimize them based on new requirements and standards.

Recently, one of our prospects who is involved in manufacturing of metal sheet enclosures faced a serious problem of failure of a particular design of the enclosure under pressure load that was supplied to a leading customer. The customer had to reject all the supplied models and due to this they were about to lose a huge order of supply as well as future orders.

The prospect was not clear about the reason for the design failure and was not sure how to fix the problem without any major design change.

Approach to the Metal Sheet Enclosure Problem

The first part was to study the entire process and understand the various methods that were involved in the design and manufacturing of the part. Through this process, it was found after an
internal study that the enclosure design was done by rule of thumb calculations and was carried out only by the work experience of some technical staff.

The approach undertaken was to perform CAE simulations via the Finite Element Method (FEM) to analyze and improve the structure of the model. The fundamental steps taken were as

● Prepare the provided 3D CAD model for analysis
● Perform a stress analysis to measure the structural deformation
● Modify the CAD model by only increasing the sheet metal thickness
● Re-analyze the modified CAD model to see if the deformation is within the tolerances

Why we selected SimScale as the CAE tool

Compared to the conventional CAE tools, the SimScale simulation platform is unique as it is completely cloud-based and provides HPC computing power (up to 32 cores per job and 240 GB of RAM) needed to perform large scale analyses. On top of that it requires only a Web browser to access and thus needs no software or hardware installations. This means you can test and analyze your designs anywhere, anytime and can save huge costs on hardware.

Another factor was the ability to upload any neutral file format from a CAD system and the option to import from Onshape (full-cloud CAD solution). It has an inbuilt post-processor that provides a simple and easy way to view the results and a nice Graphical User Interface (GUI). Here at SolidTrust we also liked the flexibility in providing the option to download results for further processing.

Overview of the FEA Simulations

CAD model RTG crane

CAD model for the sheet metal enclosure

The objective here was to check the stress concentration areas and whether the thickness of aluminium metal sheet enclosure was enough to withstand a pressure load (approx 500 N)
applied to the top face. The Type of ‘Structure Mechanics Analysis’ chosen was ‘Static Analysis’ with a linear elastic material properties as the expected load was not large enough to cause
plastic deformation. For meshing of the model, the ‘Automatic Tetrahedral’ operation was used and a study was made for getting accurate results.

The physical problem was modeled by applying fixed constraints on the 2 inner flanges and a load constraints on the top face of the enclosure using a pressure based load as illustrated in
the figures below.

load and constraints

Load conditions for the static linear analysis

Findings and Conclusions

From the FEM analysis, it was found that the original design thickness (~ 2mm) resulted in displacement areas that were distributed at the enclosure’s centre. This displacement was
more than the quality standards and was unsafe for the enclosure design.

The design was improved by iteratively increasing the thickness of the cover up to a value that resulted in the reduction of the displacement for the load acting area and to have a maximum
displacement well within the Factor of Safety (FoS) limit. Hence the metal sheet enclosure design would be safe for the given load criterion. The results for the improved thickness (~ 5mm) are shown in the figure superimposed with the enhanced deformation of original model.

RTG crane FEA analysis

Displacement contours of the improved model superimposed with enhanced deformation

The complete study was performed with relative ease using the SimScale cloud-based CAE solution. SimScale provided us with advanced capabilities to perform complicated and demanding analysis that could include highly nonlinear behavior including large rotations, deformations, physical contacts etc. Furthermore, we were happy to see that complex nonlinear material behavior including plasticity, hyperelasticity, damping and creep can also be modeled.

About SolidTrust Technologies

SolidTrust Technologies is an engineering company specialized in implementing the latest engineering technologies and products for various industries and research institutes. Backed with decades of experience working with engineering and manufacturing companies, SolidTrust has an excellent team of technical engineers and has a strong presence across all markets in India.

The company’s focus is customer service and best service quality. Learn more about it and find out how you can collaborate on the dedicated company page.

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