What is the Engineering Design Cycle

As I know it, and continue to grow with it...

Engineering Product Development Cycle

A design system is a product, and similar best practices to product docs apply when documenting a design system. Offering succinct ways to get started is a great way to introduce the concepts of your design system, while empowering folks to use it for their needs.

Specifications Specifications should be derived from interpretation of the rules, as well as the drivers needs and considerations for each system. It’s important to create high level vehicle specs as well as system level specs. These should be well documented. It should also be understood if the specifications were followed and if they changed for any reason. In addition design judges will have reviewed our submitted spec sheets and may note anything that stands out or that they have questions about. 8 For our purposes Car Specifications are top level, System Specifications are mid-level, Component Specifications are bottom-level. Research / Development R&D is an essential part of product development and there is much R&D that could be completed on the Baja car. The R&D we are looking for here is relative to meeting the vehicle, system, and component specifications that we have defined. Design / CAD Computer Aided Drafting (CAD) is an important part of engineering today. It’s very rare today that a vehicle goes into mass production without a full 3D CAD model as well as detailed engineering drawings for each part. The students should be able to show both models and drawings for both parts and systems. Incomplete or not representative CAD models or drawings can drive numerous issues in analysis, testing and manufacturing and therefore it is critical for the CAD models and drawing to be accurate. Data Collection for Analysis Any analysis is only as good as its boundary conditions and assumptions. The best way to define the boundary conditions and reduce or eliminate assumptions is to collect good data. Data can be collected in many different ways, some cheap and simple and some expensive and complex. Judges will not accept excuses like “We don’t have a large enough budget for strain gauges and accelerometers”. There are lots of ways to gather good data without expensive equipment. They will ask questions about how the data was collected and how you know it's good data. Analysis / Calculations / CAE Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), and Multi-body Dynamics (MBD) are among the types of analysis students should be performing on parts and systems of their vehicles. There are a few things to keep in mind regarding all analysis. What assumptions were made? Do the results make sense? Can you explain the models as well as the results? We should have all calculations ready to show, judges will not look in depth at these but will want to know that they have been done, these need to be complete and assumptions should be understood. Questions will be asked to ensure that we are completing the calculations and CAE to build confidence in their designs before manufacturing and testing, not just for the engineering design event. Testing / Validation Testing and validation is very important in any vehicle especially an off-road vehicle where a lot of assumptions are made during the design process. There should be discussions about component level tests, system level tests and full vehicle tests. Information about failures and how the failures were corrected is helpful. We are looking for validation that was done for a specific purpose with documented results. 9 Correlation of Analysis and Testing This is often the last step in the engineering product development cycle and is critical for continued learning and increased efficiency in engineering design. This step often reduces or eliminates the need for some testing in the future, but that may not be the case in Baja SAE. Judges will be asking how the CAE models were validated and correlated to real life? The correlation can start as a simplification, but full correlation is often detailed and complex.

Serviceability This is primarily the convenience and assurance of servicing operations, such as fluid level checking, fluid replacement, linkage adjustment, wearable part replacement, lubrication, etc. Secondarily, this is ease of overhaul (partial disassembly and major part replacement). We may be asked to define our servicing and overhaul requirements, and then demonstrate how their design facilitates these. We may be judged both on the adequacy (not length!) of the lists we generate, as well as on our design to meet these requirements. Note: engine replacement is an overhaul operation, not a field fix (i.e., Baja cars are production sporting vehicles, not dedicated racing vehicles). Engine protection probably takes precedence over engine ejection. Manufacturability/ Mass Production Design for volume production means different things in different industries with different markets, different supply chains, different labor pools, and different product characteristics. What is clear in one industry (the optimal number of bends in a tube, for instance, before it is better to make a weldment) might yield an equally well-grounded and different answer in another industry. Judges will use their 11 experience, but keep an open mind and listen to where we are coming from in this aspect. They will look for a well-considered system of volume production, and deliberate design to meet that system. Consider trade-offs between performance and volume production. Unless everything happens just right, the volume production system we describes (and presumably have designed to) will be very different from the process actually used to build the prototype. It is not acceptable to claim that a different design will be used for volume production – the prototype is expected to be accurate. But claiming different manufacturing processes to build the same design for volume production is acceptable. Something like our front uprights can be machined out of billet aluminum for competition, but the mass production plan could be to have this part cast. Innovation Bonus points Since this category is worth bonus points, to get those points the feature must be truly innovative as well as fully engineered. If both criteria are not met no points will be awarded. It should be very clear when something is innovative and the judge should not ask “what is innovative on your car?” Up to 15 points can be awarded, but there may not be a single car at the competition that gets the full points. Innovation does not have to be truly revolutionary, just innovative for our car/team.