Rapid Header Design Method Using SolidWorks in Conjunction with Spectrum5 Automated Tubing Design Software Formula 1 (F1) header design in a day... Author: W. Kurt Dobson, CEO - Spectrum5
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Spectrum5 Automatic Tubing Design Software: A fully automatic tubing design software package developed by Spectrum5 has been in successful use since 2001. This software has been used to develop F1, Nascar, Busch and many other racing headers. This software has been shown to achieve optimal designs. For racing applications, this generally involves achieving the correct primary tube lengths, maximizing bend radii for best flow all while meeting the physical packaging constraints. This tubing design software was written in Matlab, a powerful scientific programming language used widely across the sciences. A tubing design problem is setup as a nonlinear constrained optimization problem (with considerable gymnastics). As such, the algorithm needs an initial 'solution' as a starting 'guess 'for the optimization. Although the initial solution doesn't need to be very good, it is a requirement to have the basic exhaust port to merge collector mapping defined. It is also usually necessary that the initial 'guess' solution allows the optimization to converge on the correct primary tube routing. These design problems are setup in data files containing the geometry of both the desired solution and the packaging constraints and obstacles. This data is generally obtained manually from 3d CAD files and/or from 3d digitizing equipment such as a Faro Arm. Also in a data file is the initial 'guess' geometry off the solution. This file is generally prepared produced interactively with the software. Today therefore, successful use of the software requires expertise in 3d trigonometry as well as a basic understanding of the Matlab programming environment to setup a design problem. Often, this time exceeds the actual computer time of running the automatic design software. A goal of this paper is to change this so that complex tubing solutions can be designed easily without this level of expertise. This 'Setup Problem' can be solved conveniently within the Solidworks 3d CAD environment and interfaced with the Spectrum5 tubing design software through an API. SolidWorks: Solidworks is a new generation 3d solid modeling package quickly capturing the largest and fastest growing marketshare. It was designed top-down with powerful new features including an Application Programming Interface (API), which allows 3rd party applications to drive Solidworks externally, or to be fully integrated as an add-on package. A few years ago, Spectrum5 wrote a simple API application that automatically creates 3d Solidworks tubes and tubing assemblies from the Matlab software. Our customers were delighted, most of whom use 3d models to check for fit and aesthetics with their engine and chassis prior to the complex and expensive task of actually fabrication. The figure below shows a Solidworks model headers for the Falconer V12 engine in a customers race chassis designed in Matlab and automatically generated by this API.
Recently, while working on another project, a model of a manual rapid header prototyping method was developed in Solidworks as an analysis tool. An online article on this manual method can be found at: www.spectrum5.com\ice%20article.com While performing this analysis, the realization that Solidworks could be used to solve the 'Setup Problem' for out Matlab software occurred. Methodology: The analysis looked at a new manual header design methodology using "lego" like snap together blocks marketed by icengineworks (www.icengineworks.com). These modules come in kits of a particular OD with various bend radii as well as straight sections and are an excellent way to prototype a header design manually in situations where 3d cad models are not available. These modules snap together like lego's, and rotation between the modules is possible with measurement facilitated with index markings around the circumference of each part. Read the articles for details on these modules that can be used to very quickly prototype piping designs manually. Solidworks mating algorithms allow equivalent capabilities within the 3d CAD environment. In this case our motivation is to use this capability to very quickly produce an initial solution that can be exported to our MatLab software with the correct port mapping and rough tube routing. The strategy is to put a Solidworks assembly together with a merge collector, exhaust flange, and primary tubes constructed entirely from small bends mated together. The primary tubes constructed this way become discretized 'flexible' pipes, the segments of which can be quickly dragged within the 3d environment to achieve an approximate solution. When dragging segments of this tube, Solidworks 'solves' the mate interfaces dynamically, rotating the components as necessary to achieve whatever shape is required. For example, straight sections can be achieved by simply dragging a segment in the required direction. Solidworks will rotate the circular mates 180 degree's on alternating sections. Different bend radii can also be approximated in the same way. Formula 1 V10 Headers In a Day? To illustrate this, we quickly put together a 3d SolidWorks part with the correct exhaust port locations, a simulated exhaust flange, and the correct merge port locations, again with a simulated flange for the right side of a Toyota V10 F1 engine.
For this design, the primary tubes are supposed to end up being about 400mm in length. To approximate this, 17 sections of 28 degree bends were mated for each of the 5 primary tubes. The figure below shows the first primary tube mated to the exhaust port, but not yet mated to the flange.
Next, the other end of the primary segments are mated to the proper merge collector port. Solidworks automatically performs a 'solve' operation, causing the snake-like primary to unravel into one of many possible paths using the degree's of freedom defined by the mates between the segments (in this case coincident circular mates), namely rotation.
This is repeated for the remaining four primary tubes. The figure below shows the results with all five primary tubes mated. At this point, we are not worried about collisions (there are several), or routing.
The next step is to drag segments around until the routing looks feasible. After only about 10 minutes of dragging pipe segments, a reasonable looking routing is achieved. The figure below shows this solution which will be used as the initial guess for the Matlab tubing design software. Remembering that the MatLab software will do a full optimization, minor collisions, exact routing and aesthetics is not important at this stage... just a reasonable initial solution.
The extraction API software is then run which automatically gathers all the necessary parameters from the Solidworks assembly created, as well as coordinates of any packaging constraints, obstacles, and generates all the necessary geometry files for the MatLab software. In this example, the Matlab code was setup with a fixed xyz position and direction for the merge collector, but rotation plus/minus 30 degree's was allowed as a degree of freedom. Also, the primary tubes in this example are stepped, so the software was setup to converge on the desired lengths for both the initial (smaller OD) tubing coming from the exhaust ports, as well as the large OD tubing going into the merge collector. The MatLab software is then run. In this design this takes about an hour to fully optimize the design. The resulting design converges on a solution such that:
A 3d plot is shown below of the Matlab solution. The automatic tubing design software generates a complete bill of materials showing exact parameters for all tubes, rotation between segments, and dimensions that aid material cutting and assembly of the design.
Results: This paper outlines a design methodology that is capable of very quickly performing very complex tubing and piping solutions for a variety of industries. In this example, a Formula One header was designed in less than a day which included writing this paper while the MatLab software was running the solution. This design methodology utilizes the powerful features of Solidworks to quickly create the geometry and an initial 'guess' solution, eliminating time-consuming and error prone manual creation of problem setup parameters, and eliminating the need for expertise in 3d triginometry, vectors and MatLab. The proven Spectrum5 automatic tubing design software then takes over and optimizes the solution until convergence to desired design criteria are met. This software is a very powerful tool that is able to simultaneously solve all tubing, design objectives, packaging constraints and obstacles and converge on a feasible solution. This optimization on a typical desktop PC generally takes between 1-4 hours of run-time. Importantly, once the design is in the MatLab environment, changes in desired tubing length, merge collector position and orientation can be made with ease and the software re-run to produce another optimal design quickly. Once the MatLab solution is complete, the following options are available to our customers:
All of this of course, applies to other tubing and piping solutions in aerospace and other markets. Spectrum5 intends to fully integrate this technology into the SolidWorks environment in the near future and is looking for a customer/development partner to fund the effort. The result will be a completely automated tubing design software solution with broad applications in automotive, aerospace and industrial markets. Vendor Information: For more information on rapid prototyping header modules and components, see the ICEngineworks web page at: www.icengineworks.com For more information on Spectrum5 Automated Tubing Design Software, see: www.spectrum5.com For more information on Spectrum5 Racing products, ICE prototyping flanges, fabrication services, please see: www.spectrum5racing.com Author's Bio: W. Kurt Dobson is CEO of Spectrum5 and Spectrum5 Racing (www.spectrum5.com & www.spectrum5racing.com), developers of automated tubing design software and fabricator of racing headers and related components, respectively. Mr. Dobson has served as Adjunct Prof. of Electrical Engineering at the University of Utah, was IEEE 'Engineer of the Year' 1997/1998 Utah, and has authored 42 U.S. Patents (12 granted) primarily in the mathematics of and signal processing for wireless communications. Mr. Dobson is a road racing enthusiast and is a licensed SCCA and NASA competitor and road race instructor and has raced professionally in Sports 2000, CSR, GT2 and GT1 racing venues. Photo below shows author with his youngest son, and two race cars: a 1997 Porsche twin-turbo (GT2 Class), and mid-engine Ultima GTR with 1300bhp twin-turbo power (Unlimited Class).
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