Open Design Optimization Platform (ODOP) - Coil spring design app; mechanical springs; compression spring, extension spring, torsion spring
ODOP is a web software application (web app) that provides features and capabilities to facilitate the analysis and design of a broad range of problems that have a mathematical model available.
The ODOP software is being developed as open source software. The source code is freely available under the (permissive) MIT License. There are no fees associated with use or redistribution of the software. You are free to modify or customize the software to suit your needs. It is expected that various organizations may host the software on their web servers and allow free use of the software by the general public.
The ODOP software is expected to run on most modern web browsers. A very broad range of hardware and operating systems will be able to utilize the software. This includes Microsoft Windows and Apple MacOS, Linux systems plus many iOS and Android based mobile devices. As browser-based software, there is no "app" to be downloaded and installed. Responsibility for managing updates lies with the person or organization managing the server. End users will never need to be concerned with installing ODOP software updates on their system.
Calculations required by the software are performed within the browser on the user's computer. Each time another user starts work, another processor, memory and network connection is added as well. Thus, each user does their design activities in a highly responsive environment and those activities do not degrade the responsiveness of other users.
While multiple users may share the server that initially provides the web app as well as the server that stores the design library (specifically, the File : Open and File : Save operations use that server), these operations happen infrequently and at times that the user is relatively less sensitive to slight delays in program operation.
Developed as a "responsive" web app, the software will change its screen layout and input behavior in response to the capabilities of the user's device. Note that while operation on a cell phone may be possible, the scrolling necessary to accommodate screen size limitations may impact productivity.
The ODOP software can eliminate the iterative analysis process that is common with more conventional approaches to design. While certainly capable of analyzing the performance of an existing design, ODOP is at its best when used to develop solutions to difficult and highly constrained original design problems.
The user's ability to enter independent variables and compute dependent variables is the most basic of the software's capabilities. With other tools where analysis is the only capability, the designer is forced to iterate, basically guessing values of inputs in order to produce the desired values of outputs.
ODOP is very versatile in its approach to design because it has the capability to invert the dependent-independent relationships of the design equations. This means that the designer can enter his design problem in exactly the terms that it is specified. For example, when designing a spring, if force and deflection at two points are specified, the program can solve the problem without explicitly using spring rate. If spring rate and maximum load are specified, ODOP will work to a solution without explicitly knowing deflections and lengths. ODOP has the capability to handle any consistent combination of specifications on the problem.
The ODOP Search feature selects appropriate values for independent variables. In the spring design example, these might include selecting quantities such as wire diameter, coil diameter, free length and number of coils to achieve the desired force-deflection characteristics. At the same time, the program can ensure that the design does not exceed the user's specifications for values of stress, factor of safety, form factor (buckling), solid height, inside or outside diameters, etc.
ODOP contains a powerful numerical search capability that probes for the design that is specified until a satisfactory solution is found. The program can seek the constrained extreme of any variable, independent or dependent. For example, ODOP can be asked to find the spring of least material weight (or lowest rate, least solid height, greatest factor of safety, etc.) at the same time that it is maintaining all the previously described objectives for force-deflection characteristics, stress, diameters, etc. Thus, ODOP has a "goal seeking" capability that is not commonly found in other design methods or programs.
ODOP has features that allow the designer to quickly probe the range of solutions available within constraints. Returning to the previous spring design example, ODOP might deliver a solution with a relatively high stress level (a solution that minimizes weight is expected to have stresses that are close to the maximum allowable stress or minimum factor of safety constraints). The designer can ask to see a design that reduces stress (at some penalty in increased weight, of course), but still meets the goals expressed by the various other constraints on the problem.
If ODOP determines that the designer's goals (as expressed by his constraints on the problem) cannot be met, it is necessary for the designer to restructure the design in some way. One approach is to select stronger (and probably more expensive) materials. A more likely approach is to seek a compromise where one or more of the original objectives is sacrificed (for the spring design example, perhaps cycle life) in order to maintain the others (for example, outside diameter and solid height). ODOP has a feature that may be used to identify those constraints that are most leveraged and guide the designer to restructure his goals in a way that is most consistent with his original objectives.
ODOP may contain tables of material properties for many commonly used materials. In the spring design example, with most spring materials, allowable stress varies significantly as a function of wire diameter. For this reason, ODOP:Spring recalculates allowable stress and factor of safety for each combination of material type and wire size evaluated. These features eliminate the need for the designer to refer to tables and charts of material properties.
Once a designer has established a custom design that satisfies the objectives, ODOP has a feature that can select from a table of standard sizes. In the spring design example, each material can have a unique table of standard wire diameters. Standard wire diameters for both US customary (inch) and metric (mm) units are provided. Similarly, a feature is provided to select the closest or otherwise most appropriate design from a catalog of stock designs. The default stock spring catalogs supplied with ODOP:Spring include U.S. Military Standard 24585 (SAE-AS24585) for compression springs and MS24586 (SAE-AS24586) for extension springs.
ODOP can save designs into a database (design library) for later recovery. This feature has many uses. A designer can save a specific design for detailed comparison with alternatives generated later. A design investigation can be interrupted to get more information or service other requests, then resumed later without the need to repeat prior effort or the risk of introducing errors. Detailed reference information, including names and phone numbers, may be saved with each design.
ODOP maintains its complete user's manual on-line and available to the user at all times. A request for "HELP" will be answered with a list of all the features available and all the specialized topics for which help is available. The user may then pursue more detailed answers to his questions. The user can read information at his own pace and return to the design process as soon as the desired information is obtained.
The spring design example comes with carefully structured lessons to help a new user get started quickly. The tutorial will "re-play" any of several pre-arranged sessions that are designed to illustrate program capabilities and features. Other sessions illustrate problem solving techniques as well as provide sample solutions to several generally available reference book problems. Detailed comments are imbedded to explain the solution process.