Taught By Experts with Experience in Your Field
Our ANSYS training videos are designed and delivered by ANSYS experts from the BAJA Tutor Race Car Design & Analysis team, who have seen and solved a vast array of engineering simulation challenges, some likely to be similar to yours. They will transfer their expertise and experience to you as part of the instruction delivered.
Based on A Proven Curriculum
Through years of experience we have developed a proven curriculum that maximizes learning and retention, and is optimized to best utilize time spent in each class. The videos courses provide the theory behind the engineering simulation solvers, critical for understanding and interpreting the results generated. Knowing the meaning of the key input values and the use of best practices for problem set-up and result analysis greatly accelerates productivity. Hands-on exercises provide familiarity with the product and lead to quick and confident adoption.
Quad is an all terrain vehicle (a four-wheeler bike), which was initially developed as a farm-to-town vehicle in isolated and mountainous areas. Team Juggernaut has accepted the challenge to manufacture a vehicle with best performance in rugged terrains. An aspect of this project is to design and document a report that creates an overview of the vehicle’s construction element. The team focused on improving every single system on the bike to enhance performance and drivability. As a result of the design and construction process, the members learned the challenges and rewards of real world engineering projects.
The concept of a part taking shape as it reacts to its environment may be new to engineers, but nature has been doing this for a long time. Take for instance the evolution of bones—long skeletal bones will grow and change shape as they are subjected to loads and boundary conditions.
Altair’s solidThinking has programmed this bone-like behaviour into Inspire, a concept modeling application for mechanical design. Essentially, Inspire uses a bone growth algorithm to create the shape of a part from little more than loads, boundary conditions and a space that represents a maximum build volume.
Inspire is an interesting example of early concept CAE design. Instead of bringing simulation into the initial CAD design, Inspire works backwards. It will “grow” a near optimal concept using FEA simulations.
“Inspire is based on human bone growth algorithms developed at the University of Michigan in the mid ‘80s,” said Kroeger. “We mimic what nature would do. We took this high-end engineering technology, OptiStruct from Altair, and made it simple and easy to use for designers. That technology was put together with FEA solvers which essentially allowed you to figure out what the best structure is.”
Analysis During Conceptual Design
Keeping initial concept CAE tools simple is important in the design engineering world. Products can benefit a lot from simulation-based insights to ensure concepts are already near optimal in the early stages based on reduced mass, maximum stiffness, or frequency.
“Companies get more value from engineering tools the earlier they are used in the design process,” said Shaun Kroeger, Director of Partner Sales at solidThinking. “Inspire takes engineering tools and puts them in the very front, in the concept design phase.”
Maximizing the Concept Creation Potential of Inspire
“If the user uses CAD then Inspire is a cake walk,” joked Jaideep Bangal, Senior Application Engineer at solidThinking. “The most difficult part is thinking outside the box when designing a part with the tool.”
For example, Bangal told the story of a customer who designed an engine mount the same way for 10 years. When they input their standard packaging space and loads, the customer was confused to find a similar design to the original part.
“They used the same packaging space that the old part occupied as their starting point. The idea is to start with the biggest possible packaging space you have,” said Bangal. “If you force the packaging of your current optimized part you will not get the most out of Inspire. You need to think outside the box of your current packaging.”
Essentially, Inspire will mesh a part based on the packaging space. If an area of the mesh experiences a load, Inspire will keep or remove material based on that load distribution and natural bone-growth algorithms.
Seeing an optimization tool like this build a concept design out of thin air might make some engineers worry about job security. However, Bangal assures that this isn’t the case. “The main role is to create a design that works with all the parameters and is still manufacturable. All we give an engineer is a starting point. Before, engineers started with a block. We say the starting point should be our results so they don’t have to go through the iterative process.”
“Can a design engineer come up with these design[s]?” He added, “Maybe, but the easy route is an I-beam. Our results are stronger and lighter, but they also allow design engineers to come out of their I-beam cocoons. It allows them to come up with the most efficient and organic design.”
Besides, anyone can design an I-beam, and with the help of Inspire engineers can be more creative—even artistic.
For a video transcript please follow this link.
How to Use Inspire to Create a Near Optimal Concept
The Inspire workflow is designed to be simple and intuitive for use in the early design cycles.
The workflow leads engineers to move through the ribbon tool icons from left to right.
“You don’t have to be an expert to use the tool,” says Bangal. “It takes about 4 hours in our training class to become productive. We have even had a few customers watch YouTube videos to start using it … And if you do make a mistake, you can hit ‘ctrl-z’ any number of times to undo the last action.”
Though Inspire isn’t a CAD package it does have some sketching abilities. This allows users to start from scratch by building a packaging space. Alternatively, users can import a design or revisit an old part by importing a CAD geometry. However, Bangal reminded users to “not constrain yourself to the existing geometry pockets. Remove fillets, holes, and increase the packaging space as much as you can.”
It takes a detailed eye to create a CAE tool focused on usability. For instance, take the mouse pointer icons within Inspire. The pointer icon will change based on the part feature you are hovering over. This helps engineers to determine what they will select when they click the mouse. There is a different mouse pointer for points, curvatures, faces and edges.
The tools in Inspire work in a similar fashion. This means if you learn the workflow of one tool you should be able to use the others. “The load and support definition is common to the contact definition. The program also doesn’t default to pull down menus or model trees unless the user prefers to use them,” clarified Bangal.
With the geometry built, users can then set displacement constraints, boundary conditions, materials, and loads onto a part. When defining a mass loading, for instance, “you don’t need to draw an engine in CAD,” said Bangal, “all you need is a center of mass, where it is mounted, and how much it weighs.” As for the material definition, users can choose from a library or create their own. Users can also define multiple load cases to ensure the part is optimized for all use cases. When inputting these values, users don’t have to worry about keeping their units. Inspire will keep track of units.
For most CAE software the next step is to build a mesh based on your geometry. Given the role that the mesh plays in Inspire’s optimization of the part, it is surprising that users have little control over mesh generation. To ensure simple usability and quick turnaround, Inspire builds the mesh automatically.
For instance, localized mesh constraints would be useful to engineers that are concerned about the force distribution involved at a certain section of a part. However, the current control of the mesh is limited to the definition of the following global parameters: minimal part thickness, minimal element size and average element size.
Therefore, once the boundary conditions, loads, and packaging space are defined the user determines the goal of the study. They can optimize the concept part based on maximum stiffness, minimal mass and resonant frequency.
“The maximum stiffness is based on the given loads while the minimization of mass is based on a given factor of safety,” clarified Bangal. “Frequency optimization ensures that the part is designed to avoid a frequency.”
Once the concept part is created, users can run FEA analysis within the Inspire platform to assess the geometry. This will help the engineer to determine which concept designs to pursue with their CAD programs.
Bangal explains that Inspire will make designs that are organic and mathematically correct to handle the given loads and boundary conditions within the current packaging space.
However, due to the organic nature of these shapes, there may be no means to fabricate the design using traditional manufacturing practices. As such, the concept parts are often constructed first via 3D printing.
However, “We realize that not everyone has 3D printers yet and there’s a lot of traditional manufacturing,” said Kroeger. “So we have shape controls in our solver that force the answers to be something that could be cut out of sheet metal, or something that could be cast. That really allows any user to benefit from Inspire.”
Once satisfied with the geometry, engineers can send it to CAD to finalize the design.
“Inspire uses Parasolid as a communication mechanism,” said Kroeger. “So we can actually read in CAD files directly and we write out Parasolid of these ideal shapes. Then you can bring that into your preferred CAD software, and use that to start your designs.”
This model transferability stresses the point that “the result from Inspire is still a concept part,” said Bangal. “Engineers will have a better idea of the final changes the part will need. But with Inspire, many of our customers were able to experience massive savings for their part, some almost halved the weight.”
In order to avoid from bending which is more worst then compression and tension, tubes should be arranged to form triangles with the major loads applied at the intersection of tubes.
In comparison to straight tubes, bent tubes have more chances to get buckled. It is seen bent tubes are better than butt welds (which should be avoided), but still not as good as node formation.
Add diagonals in roll cage if it is already made and is too flexible. Diagonals work best if it is connected to major load points ie spring suspension mount.
Add additional cross members to the chassis.
Some of the tubes are AISI 1018 , AISI 1020 , AISI 1022 , AISI 4130
For fire wall and other roll cage member, bent steel tubing is better than welded lengths of tubing. You don’t have to worry about heat stress to the tube.
Bent should be done accurately according to analysis else it will result into negative effect. Do not use pipe bender to bend the tubes because the dies do not fit correctly. HF “kinker” is infamous for terrible bend on tubing.
A proper fitting and tight notch are extremely important for strong weld joint. End mills and lathe are most common notcher machine. Some expensive machines are end mills and abrasive belts.
Even though nodes are the strongest point, too many nodes are not allowed at one point (3-5 tubes). Maximum tube node should be selected as shock mounting place it helps in proper distribution of load.
Shocks and lower A-arms are the most stressed segments of the car. In places where you can’t use tubes to form a node, you can try metal plate with flared holes that can be pretty rigid although round tubes offer material in all 3 dimensions for added strength.
The apex of bend should be node point or junction for at least one another tube, and gusseted unless several tubes meet at the node. Never leave bent tube unsupported.
It is advisable to gusset corners, especially when building a bare minimum cage. This can be done with triangular plates welded into the corners. A stronger method is to weld a 6-12” tube diagonally in the corner, similar to the letter A. when using plate as a gusset, never have sharp angles try to curve it because it tend not to crack as much in tension.
Different types of tube
Mild steel also known as carbon steel (Containing a maximum of 0.29% carbon ) or plain steel. Typically, it is stiff and strong. Carbon steels do rust easily, so they must be painted or primed. They are cheap so they are the normal choice for most fabrications. Mild Steel can be easily cut, drilled or welded to meet your requests, making it suitable. Mild steel tubing is typically made from sheet that is rolled and welded. The alloy is 1010 or higher. It is no strong as compare to others but it has tendency to bend before breaking.
Drawn Over Mandrel Steel tube is manufactured in the same way as mild, including welding. The alloy is typically 1018 up to 1026, Higher the number, the higher the carbon content and stronger the steel. Dom is a process which hides the weld giving it more accurate dimensions, which also strengthens the tube through cold working. Its cost is double in comparison of mild.
It is usually a true seamless tube, with chromium and molybdenum added for strength. It is lighter with thin wall but as strong as thick wall steel tube. It is expensive and needs heat treatment after welding to achieve maximum strength.
The chromium content is approximately 0.8-1.1%. The carbon content is nominally 0.30% and with this relatively low carbon content the alloy is excellent from the fusion carbon content the alloy is excellent from the fusion heat treatment. The actual breakdown of 4130 alloy steel is as follows:
Carbon 0.28 – 0.33
Chromium 0.8 – 1.1
Manganese 0.7 – 0.9
Molybdenum 0.15 – 0.25
Phosphorus 0.035 max
Silicon 0.15 – 0.35
Sulphur 0.04 max
4130 low alloy steel is used as structural steel in aircraft engine mounts and welded tubing.
It can be easily machined in the normalized and tempered condition, as machining becomes difficult in fully heat treated condition because of increased strength.
Formability is best in the annealed condition for which the ductility is very good.
4130 is a steel and as such is not corrosion resistant. In corrosive environment the alloy should be given a protective coating.
4130 alloy is noted for its weldability by all of the TIG.
Heating at 1600 °F followed by an oil quench will harden the 4130 alloy. For best results a normalizing pre-hardening heat treatment may be used at 1650 to 1700 °F followed by the 1600 °F soak and oil quench.
Forge at 2200 °F maximum down to 1750 °F.
Hot Working-4130 in the annealed condition has excellent ductility. Thus it is usually not necessary to do hot working to form parts. If hot working is needed it can be done in the range of 2000 °F to 1500 °F.
Cold working by conventional methods is readily accomplished on this alloy.
4130 (and most of the other low alloy steels) may be annealed at 1550 °F for a time long enough to allow through heating of the section size. It should then be cooled in the furnace at a rate of less than 50 °F per hour down to 900 °F, followed by air cooling from 900 °F.
Tempering is done to restore some of the ductility that may be lost after the hardening heat treatment and quench. Alloy 4130 is tempered at between 750 °F and 1050 °F, depending upon the strength level desired. The lower the tempering temperature the greater the strength.
The 4130 alloy is a through hardening alloy and should not be case hardened.
CREW = Cold Rolled Electric Welded
HREW = Hot Rolled Electric Welded
ERW = Electric Resistance Welded
CDS = Cold Drawn Seamless
DOM = Drawn Over Mandrel
HFS = Hot Finished Seamless
CDBW = Cold Drawn Butt Welded (Continuous)
W&D = Welded and Drawn
“T” junctions are called a dead tube junction, as one tube dead ends into another. This should be avoided whenever possible, because the dead end tube will bend the other one when the loads are along the dead tube.
“A” pillars should not be leaned back too far, unless a second A pillar is added to triangulate it. Otherwise it can collapse into the passenger compartment. The B pillar will be strongest when near vertical. It is always safer to double up on the A and B pillar on heavier vehicles. All cages benefit from a vertical tube in the windshield area. An inverted “V” like this is even stronger.
The B hoop should have an “X” built into it, or at the very least a diagonal or a V. If the A and B hoops are inverted U shapes, the “spreader” tubes that go between them should intersect the apex of the bends for greatest strength, and they should be straight. The roof area should have a V or X built into it, depending on overall design. The B hoop needs to have rearward supports, typically at a downward 45 degree angle. If the B hoop does not have an X, then these tubes definitely should.
On vehicles with sheet metal bodies or cabs, the A and B pillars should pass through the floor and weld solidly to the frame rails or tubes. No tube should ever terminate like a “T” into sheet metal, such as a floor or firewall. If necessary, it is acceptable to weld a plate to each tube, on each side of the sheet metal, and use four bolts to connect them together, but only if the cab is solid mounted to the frame. Otherwise the sheet metal can tear when the cab flexes on rubber mounts. The least desirable arrangement is to keep the rubber mounts, and tie the cage into the mounts.
When tying the cage to the stock frame areas, try to spread the load by incorporating more surface welds, this can be achieved by using plate or some type of boxed gusset. Reason for this is so the tube is less likely to rip out and on “C” channel frames box in or run a tube between the “C”.
In general, TIG welding is considered superior to MIG welding, but a proper MIG weld is completely acceptable and just as strong. Tube splices and repairs should always be sleeved for strength and rosette welded, never just butt welded.
Tubes should intersect at an angle 90 degree normally. Dimple dies plat is good for making plate more rigid. Displacing material from the center of mass improves stiffness, stiffening areas of large deflection will improve an overall part’s strength. So in effect you could have a lighter and stronger part overall if you use a dimple die correctly(Dimple die installation video). Cavitation is a good way to tie two plates together to strengthen the load laterally.