GOING INTO ANALYSIS

Using the right tools, in the right order

Bruce: Hey, Benny, I need to talk to you about ... wait a minute, why do you have a baseball bat?

Benny: I’m just practicing my swing. Sometimes I do that when I’m trying to work out an engineering problem. What’s up?

Bruce: I wanted to show you the results of the FEA [Finite Element Analysis] on that engine part we’ve been working on.

Benny: Oh, great! I was just wondering about that. How’s it going?

Bruce: I’m almost finished with the analysis but I need to confirm the results afterI complete the MFA (Mold Flow Analysis).

Benny: You know, although we’ve got great analytical tools to use these days, sometimes I wonder if we are getting the most out of them.

Bruce: Well, that old saying “Use the right tool for the job” really is true when it comes to developing great new designs for our customers.

Benny: Yeah, I’ve been thinking about not only using the right tools, but using them in the right sequence. It’s a little like baseball. You have to get in the batter’s box first, or you’re just going to hit air.

Bruce: And I’ll bet you hit a lot of air, don’t you. Anyway, I was thinking that it’s sort of like saying “Ready, fire, aim!” If the order isn’t right, the results won’t be either.

Benny: That works too.

Bruce: So, on this engine oil tube application, where the customer wanted us to develop plastic component to replace their existing metal one, we knew that pressure drop would be a concern, so we first modeled the existing part using CFD (Computational Fluid Dynamics) software to benchmark the flow rates and pressure drop across the existing system.

Benny: And once we knew how the existing part performed, we evaluated a number of possible configurations that would lend themselves to injection molding.

Bruce: Right. Using CFD software, we essentially designed the “hole” geometry first to make sure that the new plastic part would have a pressure drop equal to or less than the existing metal one over a range of flow rates.

Benny: To me, it seemed a little like designing the hole in the doughnut first and then building the doughnut around the hole. Bruce: I love doughnut holes.

Benny: Yeah, me too, but it’s just an analogy, Bruce. Don’t get distracted.

Bruce: Okay. So, after we sized the “hole” we added material around the “hole” and performed a preliminary FEA to ensure that we had adequate wall thickness to handle the operating pressures.

Benny: Didn’t we also have to compensate for lower material modulus and strength since the engine oil temperature was fairly high?

Bruce: That’s right.

Benny: You know, I was just thinking, we’ve successfully converted a lot of metal designs into plastic and saved our customers a lot of money. I wonder what that number adds up to?

Bruce: Now who’s getting distracted?

Benny: You’re right. Back to that tube project. After we developed the initial design in plastic, we used Mold Flow analysis to identify the best location for the gate and also obtain the orientation of the glass fibers in the molding process.

Bruce: Which brings me back to where I am on this project. Once we have the glass fiber orientation, the molded material is no longer isotropic. That means that the material behaves differently when loaded in the direction of the fibers than it does when it’s loaded transverse to the fibers.

Benny: Yes, the fibers really make the plastic strong when it’s loaded in the direction of the fibers but weaker when it’s loaded transverse to the direction of the fibers.

Bruce:That’s why it’s really important to use a tool like Mold Flow to simulate the fiber reinforcement orientation after molding.

Benny: Well, we still have more work to do, right Bruce?

Bruce: Right. After getting the fiber reinforcement orientation, we have to perform another FEA, taking into account the anisotropic properties of the molded material. Benny: Somehow I think we’re getting near the end, right Bruce?

Bruce: Yes, this last FEA essentially will tell us if our new low cost plastic tube will give our customer the necessary performance and durability.

Benny: You know, Bruce, when you think about it, it all makes sense. Using the right tools for the job and using the right tools in the right order. It’s a good thing RL Hudson has invested in the analytical tools that allow us to do these really cool projects!

Bruce: It’s all about doing the right things right!

Benny: And hitting a home run for the customer. Bruce: I should have known you’d work that in somehow.

Solutions 1Q10

GOING INTO ANALYSIS

Using the right tools, in the right order