Monthly archive for November 2014

How the CAFE Standards Influence Engineering & Design

How the CAFE Standards Influence Engineering & Design

We were all taught about idealized cantilever beams in college.  Little did we know then, that even the simplest of parts have their own histories, and are affected by things as seemingly out of place as government regulations.

For example.. Let’s say you are awarded some new business.  Your client wants a simple bracket – The length is 20″, and it is supporting a concentrated load 500 pounds at the end.  The other end is mechanically grounded to a 5″x5″ patch.  The safety factor with respect to yield must be greater than three.  And the maximum deflection must be no greater than 1/4″.

You bring this to your design engineer, and they return with a simple rod with appropriate attachments at either end. All good and well.

Six months go by.  You client, an automotive manufacturer, informs you that due to ever constrictive standards imposed on them (and therefore, you) by the Federal Government’s Corporate Average Fuel Economy (CAFE) regulations, your old design must meet the same design constraints, but be lighter.

“How much lighter?,” you ask.

“The lighter the better,” they answer.  “Oh, and by the way – we’ve added a design constraint:  You need to keep the first resonant frequency greater than 200 Hertz.”

That’s the bad news.  The good news is that the now the end load is smaller.

You agree, and take the new requirements to your design team.  They come back with a tube design.

This happens every year for a few more years.  The CAFE requirements force progressively lighter designs.  Customers (and therefore, the client) are increasingly pressuring to keep costs down.  The form of the design becomes more distinctive over time.

After several design cycles, the constraints overwhelm your design team.  It is apparent that a simple tube design will no longer meet project requirements.  You decide to quarantine your team for a few hours, so that everyone can brainstorm about how to stay in the good graces of the client, by helping them stay in the good graces of the government.

Some interesting things come out of that exercise.  None of them are feasible.

Everyone has contributed to the discussion except one.  He’s the young, quiet guy in the back.  He looks a little embarrassed.  You convince him to spit out whatever he’s thinking.  And so he does.

It seems that when he was in school, he attended a tour of a hydroforming factory.  He tells you that this would be an ideal application for hydroforming manufacturing.  Hydroforming for example, would allow you to put ribs in your tube – something that can’t be done with conventional forming.  You’d have the extra stiffness without the extra material.

Naturally, you need to farm this out to hydroforming specialists.  As it turns out, it was a good decision.  Your VP even tells you so (happily), at your next yearly review.

Here at American Hydroformers, we are in the business of bringing success to automotive companies struggling to meet the demands of the consumer, the customer, and the government’s CAFÉ standards.  For more information on how our hydroforming solutions can help your company keep current with the cafe standards, please contact us.

In House Finite Element Analysis Capabilities

In House Finite Element Analysis Capabilities

Finite Element Analysis (FEA) is an engineering simulation discipline that has its roots in the aerospace industry, during the 1950’s.  Since that time the discipline has ‘come into its own,’ spurred by the progress of computer hardware and software technologies, coupled with aggressive competition between software companies specializing in FEA products.

While FEA applies to many engineering fields, it is most often understood in terms of structural analyses for mechanical engineers.  A typical question addressed by FEA analysts would be, “Will a part fail under such-and-such loading (forces and restraining) conditions?”

Our company is a little different in that the questions we address by our FEA simulations.  Our simulations answer questions like, “what are the prestresses caused by the manufacturing process?”  Or, “Will the prestresses of the manufacturing process cause failure in the client’s part under the conditions specified by the client?”  And finally, there is always the iterative process of changing a manufacturing process within the virtual world of a given finite element analysis, to perfect the process.

One might ask, “Why not just do actual experiments?”  We would of course arrange to do such tests for our clients.  However, the problem with the more established ‘Make and Break,’ approach compared to FEA is additional (1) timing and (2) expenses loaded onto a given project.  These factors make it prohibitive for project engineers to rely exclusively on laboratory testing.  FEA usage cuts down on the time in the design phase of a project, a phase which affects all others in the product development process.

As an added benefit – when FEA analyses can be standardized (as we have with our hydroforming simulations), significant time and cost savings can be achieved that would not be possible using the old ‘Make and Break’ product testing methodology.

For further information about how our Finite Element Analysis capabilities may achieve cost savings and enhanced structural performance for your products, please contact us.