Did you know that the science for analyzing how a material or design withstands stress was developed over 70 years ago? No, not emotional stress, like what you would use a squeeze ball to alleviate, but physical stress from outside forces such as gravity, chemical corrosion, and impacts with other objects.
The Origin of Stress Analysis
According to Virginia Tech’s Introduction to Finite Element Analysis, this science was “first developed in 1943 by R. Courant, who utilized the Ritz method of numerical analysis and minimization of variational calculus to obtain approximate solutions to vibrations systems.” Basically, Courant found a way to mathematically predict how vibrations could affect a structure or object.
Later researchers would build on this concept, refining it until finite element analysis (FEA) was born. This system of using computer modeling to analyze a material or design and calculate the effects of different stress factors on it has proven incredibly useful to design engineers over the years.
Today, we tend to refer to this as stress analysis.
Modern stress analysis is handled with the assistance of powerful computers.
When the concept of stress analysis was first created, the sheer processing power required to make calculations made it so that only big mainframe-style computers could run the software. As a result, the use of the software was limited to use by companies in the aerospace, automotive, and defense industries who had the mainframe computers needed to run it.
In recent years, however, computers have become much more capable, and the cost of a system that can run the physics simulations used by stress analysis software have gone down, opening up the software for more widespread use.
How Does Stress Analysis Work?
In stress analysis, an object is broken down into thousands of individual points, or nodes, which are integrated into a virtual grid, or mesh. This mesh is programmed to simulate the material being tested and its properties.
According to the Virginia Tech article, “Nodes are assigned at a certain density throughout the material depending on the anticipated stress levels of a particular area. Regions which will receive large amounts of stress usually have a higher node density.”
The more “nodes” there are in a given area of the simulated object, the more detailed the simulation of stress on that spot will be, which is why high-stress areas are usually assigned more nodes.
Stress factors are then applied to the virtual mesh of the structure being tested. At Marlin Steel, this structure is typically a custom basket design.
Stress factors that can be tested for include:
- Heat stress
- Fatigue from repeated loading/unloading of the basket
- Vibrations (such as from ultrasonic parts cleaning)
- Chemical corrosion
If these stress factors would cause a physical deformation in the basket design being tested, it will show up as a colored region in the image.
Benefits of Stress Analysis for Custom Parts Washing Basket Designs
So, what are the benefits of stress analysis? Why would a manufacturer run a virtual simulation of the effects of different kinds of stress on a manufactured object?
First, the use of stress analysis software can allow a manufacturer to save money and materials on manufacturing and physically testing a product. Not only does this require tooling to be made, it requires labor and materials to be consumed for a very limited production run that is not being made for sale.
Second, virtual testing using software such as Autodesk can be carried out incredibly fast. Some defects in a design might take weeks or months to become apparent through physical testing. In that time, a production run of flawed designs might be approved for production, only to be rejected when the flaw in the prototype finally emerges. Virtual testing can simulate months or years of exposure to common use conditions in mere minutes.
Finally, stress analysis testing helps keep a particular part from being over-engineered. For example, Marlin Steel’s engineers ran a stress analysis on a basket design created for a customer to hold parts weighing 420 lbs. The engineers simulated a load of 442 lbs., about 5% more than the designated 420 lb. limit, and saw that the design was more than sufficient to the task.
Marlin’s engineers found that with a little rework, the basket design would save some material on the design, reducing costs for materials and time to manufacture while still meeting the weight tolerance requirement.
Overall, the use of stress analysis programs such as Autodesk has helped to massively improve the speed and reliability with which Marlin Steel can create custom parts washing baskets and materials handling containers for clients in a variety of industries. How could you benefit from such stress analysis?