Autodesk University Automotive component lightweight design by advanced material and Moldflow Insight, Helius and Abaqus Co-Simulation

Transcription

1 Autodesk University Automotive component lightweight design by advanced material and Moldflow Insight, Helius and Abaqus Co-Simulation Hey. Hello, everyone. I'm Jian Zhang from Guangzhou Automotive. Thanks, Jimmy. Next, I will use Chinese to begin my speech. First, he would like to and the Guangzhou Automotive Corporation, located in South China and-- sorry-- That's OK. South China-- OK. OK. Sorry about this, folks. OK. GAC Engineering is located in Guangzhou, which is South China. And they are mainly responsible for their local-owned brand called the Trumpchi. The company was established around 10 years ago. And you can see the second car model, GS4, which is one of our most popular sold car in China market. Thanks to the contribution of the team during the last 10 years, they established quite a strong engineering team. There will be five engineers in the team. In Jian Zhang's team, there are two professional engineers and three guys, one of the engineer,

2 and the other, someone who is very familiar with structural designs. The reason we want to use co-simulation because in the actual, physical world, there would be assembling single physicals there. There will be multi-physics there. So for example, for this kind of multi-physics co-simulation, we have to consider some kind of processing defect from the other side, like processing from the injection molding and putting those kind of defects into the next step of structure stimulation. So today, our topic will be focus on the mold flow and structure simulations. Here, remember, that's around five years ago. There's also tools called, I think, Moldflow Structural Alliance. They can use those kind of command-- can go back to OK. --those two commands up there to export those kind of processing like a or other influence to the next step of structure simulation. Yes. With a new release tool of the Helius by Autodesk in last year, now we can have the new process flow. You can see that we can import and export the injection molding without and go into the next step of Helius and go the next step of the structure simulations, which is a much more convenient and easier than the previous tools. With the lightweight concept, we'll be going deeper into the automotive industry. And those kind of fiber reinforced material will be more and more used in automotive industry. With those kind of very unisotropic material, those kind of influences

3 should be considered into the next structure simulation. First, I'll show you some of the fiber influence for the material property. You can see along the flow direction, which is fiber reinforced the most strongly direction. And there's kind of a very good strong and tough material. But going to another perpendicular direction, there would be very soft but flexible directions and vice versa in the center. This will be something between along 45 directions. Sometimes flow direction and perpendicular direction. The difference could be 1 times and more. Due to this kind of very strong, unisotropic behavior, we should consider those kind of fiber reinforced material properties very clearly into the next step of structure stimulation. So, I'd first like to share the one demonstrate case. That will be a very simple part. One case is we're using single gate. Another one is using the two gates flow two directions. The difference, you can see the second case there would be a very strong weld line, which can cause the very strong turbulence of the fiber orientations. There will be the case where load is something like this, like a hook structure. And they will be fixed in the top and the load will be loaded at the lower hook positions. And it will be tested with three cases. The first one will be without more flow, very isotropic material. Second case will be single gate direction without any weld line. So third case, there would be two gates with weld line factor inside. For the case one, the next will he happening the centered position very

4 uniformly, the second case. And there would be also uniformly but it's very much smaller than the first case. In the third one, they will be very concentrated in the weld line position. The value also is the most biggest one in those three cases. Due to the single gate, you can see the fiber orientation around the first case very uniformly along one direction. So that can further reinforce the whole structures. That's the reason you show the smaller here. So, we'll first show the demo case, which is not realistic. But later on, we will share some cases which is used already in the engineering field. So this is the part called the tray battery. Tray, this is for battery, support the whole structure on the hold inside of the car. And in the actual test, we found a failure. Like, you can see the highlight position here. Due to the failure in the test, we do some several kind of simulation to find the root cause. You can see there's tests with four cases, which is the load condition inside of the vehicle. Watch it bounce down, bounce up, turning direction, and the brake. And after the calculation, they found the maximum stress will be happening in the bounce up load cases. After the very traditional simulation, which is isotropic, they found that the maximum stress around 62.4 megapascal, which is much lower than the fracture, around 78 around, which it should not be failed. This is a traditional series tell us the result.

5 You can see this dimension and structure of the whole part, and which is-- also, injector is one hot gate. The material will be polypropylene with 40% long glass fiber reinforced material. This is 40% long glass fiber enforced material. They will be very strong unisotropic property inside. So that's the reason they want to consider those kind of fiber effect, reinforced effect, into next co-simulation steps. Due to the concern of the isotropic, they put the moldflow-- result and also they tested the material with three directions and combined the three directions into one material fiber and map into the important for simulation, the cases, and testing the vehicle conditions. OK, I think for this process flow, I think the moldflow simulation is easy and mapping is also easy because software, they can help you to do it. It's quite easy. Most of the difficult here will be to measure the material along the three directions-- like, perpendicular, along fiber, and also 45 degree. So in most of cases, they get the material property from material supplier and fit it into the final MET file. I think the mature probably would have been mostly influenced the final result of the accuracy. And those kind of tests-- during the test of the specimen, they found the specimen size, direction, and what kind of method you produce the specimen will strongly influence the final result, which is also very, very important for the simulation you get the right material property And they also visited to the moldflow lab in in the east of the US, United States. And this kind of a visit gave us very strong confidence about the material property

6 And this kind of a visit gave us very strong confidence about the material property measurement. And also with help, we know that in further development of the moldflow, they will measure more and more and more and more accuracy of the high quality material. He will not describe too much about detail, how they measure it. But in, this will be very difficult. Then also, you should get much more support from moldflow side. Afterwards, the mapping of the fiber orientation, they found the maximum stress increased to 90 around megapascal, which has already exceeded the fracture stress. Now it's already in line with the actual test results. In the traditional, which is isotropic, you cannot notice these kind of problems. So that's what we found on the fiber orientation. It really has a big influence on the final structure result. They also found the root cause of the orientation caused the failure and because the gate location has the same line with these corners, which is the shortest wave of the flow past, flow front. When the flow front flows into this area, there will be bifurcated flow, which has caused the fiber orientation not to very strongly align. And this is, of course, the stress concentration reason here. So we'll go back to show the vehicle condition load cases. The battery tray is on

7 the side of the battery on the bottom. And there, we want a strong bracket. And the link was two steel beams. And those kind of vibrations would cause the structure-- this kind of stress concentration there. The corner brace is already-- a structure point of view, this is a weak point. And also from fiber orientation, this is also not a weak point. Those two weak points happen together because of failures. After finding the root cause, you have to find a solution. There can be two parallel ways. One is to find the structure weak point there. We can modify the design to reduce the stress concentration. But according to the-- normally after the production, it will be very difficult to change design. There would be a long process and you need to do a lot of tests to do it. Normally, it's not allowed for the timing consumer conditions. Alternative solution would be to change fiber orientation along the direction we need. So we wanted the fiber orientation along these kind of directions. So we need to change the molding tools and change the gate location to along the fiber direction we need. So we offsetted the gate location from center to a little bit side to change orientations. And the flow pattern changed. And also, the orientation changed here.

8 After they changed the location and do the co-simulation again, they find the stress reduced to the value which is lower than the fracture stress. After the physical change of and the retest again, the failure never did happen again. The case is to show you previously, there will be a case which is not that good because they found the problem. And they used co-simulation to change it, which of course cost and time consuming. But actually, the simulation, the value of submission, would be predicted failure. And we solved the problem in the very early stage. Then, the next case we'll show you, the case something like early-- solve the problem in the early stage. The second case will show what the front end model on the front end module would be on the of the part, the whole cooling package, including the radiator, fan assemblies, and also they will take the load from the locker and headlight. Module-based design concept is more and more into the automotive industry in there because they can deliver the package from the tier one to the OEM. That will be easier for assembly. And those kinds of front end modules were made by plastic material. This actually is very crucial to the strength and the stiffness requirement. But with the design freedom of the plastic material, they can make those kind of module-based design. The dimension of the front end of the module is quite big. It's one meter long. They were 600 meters high.

9 We're using the six hot gate injection and the material will be polypropylene plus 3% long glass fiber reinforced. Because we wanted one of the criteria inside would be stiffness along the direction, because the whole-- they have the locker stiffness direction requirement. After simulation, they found the stiffness-- they simulated around 600 around meters, Newtons per millimeter, which is already over this target of around 500. Because of the design concept in the automotive industry, they don't want to have a high stiffness and they're over-designed. They want to reduce the stiffness by kind of changing design. In a normal simulation, and we compared with a test, the normal isotopic way predicted stiffness normally is lower than the actual test result. So, they want to use co-simulation to not something roughly, but something accurately, which is the right stiffness for the part which it actually would be. The process will be exactly the same as the previous case. But first of all, we're using moldflow to get the fiber orientations. Besides the Helius, there also are other tools available in the market to do the co-simulations. So they want to compare and do the benchmark test to see that difference would be software.

10 Then after they get the fit in those kinds of software, they found there would be some difference between the actual curve and the test curve. Which is, if you're using the-- normally, the software, they cannot take the curve input. They have to fit into the material parameters and regenerated curve. So would be some difference here you can also see the picture there would be some difference there With the isotropic material, they found a stiffness of 600 around. But if you're going to another isotropic software, they the simulation with 560 around Newtons per millimeters. The target is 500 here. With this kind of method, they should find the simulation results actually will be lower, much lower than the isometric. With this small gap, they don't have strong confidence to reduce the thickness to make some further light design. And with Helius, we also do with those kind of material fitting inside of the interface of the software because fitting and actual curve there. They find the software is really smart and easy to use. They use the fitting of the material and everything handled by the software itself. The other software, you will need a lot of manual input to modify some factors, parameters, to fit the material curve, which is not convenient for them.

11 In Helius, you just need to put everything from a input, whereas the stress-strain curve and the angle, degree inside, there will be everything handed by it. They will show you three different results. One's isotropic and also isotropic by other software and also isotopic from Helius. Using the Helius, they found the result is even smaller, which is very close to the target. The final decision is not to change the design or it's a light weight-- a more aggressive light weight design because they found due to the variation of the actual product-- so they found this kind of small gap. It's only enough to ensure this kind of variation. So they don't want to make it more aggressive. So, they like to produce it and make it and test it in the to find the real difference. They found experimental result 540. So we can the result and the comparison here. With the help of the unisotropic software, they found the results will basically will be very close, much closer than the isotropic result. And the difference will be within 5%.

12 So, due to kind of effect here, so we have to say that the influence of the fiber reinforced shouldn't be considered into simulation. So co-simulation wouldn't be the solution for it. Today, what we show here is only the fiber orientation influenced to the final structure result. But in the future, with, there will be much more influence into like a temperature or whatever you want in putting the next step of the co-simulation stage. The influence will be the assembly deformation and also the residual stress from the moldflow simulation. And also there's the weld line fact. I think some of you maybe already lessened the cost yesterday. They already introduced about the Helius, a new feature for the weld line fact calculation. But here, we would like to appreciate the effort from Autodesk here, and get the voice from customers. In the future, there is low pressure injection and those kind of RTM copper fiber reinforced over fiber material would be next step of the co-simulation. So we'd like to keep working and it will improve continuously for those kind of simulations with a lot of. And also, we would like to get more support from Autodesk to make it

13 better. Thank you. Anyone have a question? Simulation. Dynamic to full, This one? Oh yes. Who In my eyes, very, very, very The first, I think I would like to say the design of the runner here is not based on the flow balance. I think flow balance is one reason we consider including this case. But another, much more important reason, would be the weld line positions. second can be

14 Oh, no, no. complexities So, usually this kind of speed of the situation. Take a maybe it's not the final speed. This is a-- you got I would like to say, 2.53 seconds, they can feel the. They really need a big and a big injection machine. This is the actual case I would like to see. For normally, the injector would be three to four seconds. It's possible. And you should have inject it faster. Otherwise, there will be cold material inside. So this is the philosophy inside. We made it before. Today, a view of the factory. I think that even bigger part, even bigger than this. Yes, I know. I know. I have a that the more that size of the Yeah. So, usually that is ignition time. And said that ventilation is a problem cannot make a gas for every air inside a. So, using as a low speed five second is having that-- Hm? He said the actual cases for this one is four seconds-- four seconds. Yeah, why using four seconds I would like to say that for co-simulation-wise, there will be some

15 that's fiber orientation will be most important reasons. But it doesn't matter using this speed. They will change them a little bit but will not strongly influence the fiber orientations. It's not-- very Look I have a the speed flow is a different flow. Yes. Flow is a very big change of the Understood? I understood. Yes. So I ask you your using a the time to at that time Basically, I would like to say concern is right, and using the correct time and from the tubing and get the right temperature of. But in this case, they do everything in the early stage before the building. Yeah, OK. Just verification It definitely can be changed the parameter and reflect what actually the condition, what it would be. But in the early stage-- and also the first case for them. So it would be a little bit difficult to consider, like, not everyone experienced as you to design those kind of features like extra flow site. This is how I would like to see. Thank you. Any other questions? first, I want to thank our guests. They came from very far to do this presentation, so I want to thank them for coming all the way here. So thank you very much. Thank you.