A new computerized design manual from the Aluminum Association can dramatically speed up and improve the accuracy of design engineering of aluminum parts and assemblies. The Aluminum Design System (ADS) is a computerized version of the Aluminum Design Manual that is far more powerful than the paper manual because it not only explains how to solve a problem, but also actually performs the required calculations. The software also includes the ability to perform parametric analysis, solving for multiple input variables in order to determine an optimum solution.

The Aluminum Association, Inc. is the trade association for U.S. producers of primary aluminum, recyclers and semi-fabricated aluminum products. Headquartered in Washington, DC, the association provides leadership to the industry through its programs and services which aim to enhance aluminum's position in a world of proliferating materials, increase its use as the "material of choice," remove impediments to its fullest use, and assist in achieving the industry's environmental, societal, and economic objectives. Member companies operate more than 300 plants in 40 states.

One of the Aluminum Association’s main tasks is developing and maintaining the design specifications for aluminum structures, and publishing them in the Aluminum Design Manual which serves as an industry bible for the design of aluminum structures. Considered to be the most complete manual on aluminum design ever published, this comprehensive, up-to-date resource includes: 1) Allowable Stress Design Specifications, 2) Building Load and Resistance Factor Design (LRFD) Specifications, 3) Design Guide, 4) Materials, Material Properties and Section Properties, 5) Design Aids, including Beam Formulas, and 6) Illustrative Examples of Design.

Improving the paper manual

The Aluminum Association recognized the opportunity to dramatically improve the ease of use of the Aluminum Design Manual and the design specifications included therein. The time required to identify the proper formula for a given problem and manually perform the calculations can be quite lengthy. The concept of ADS was to provide both a searchable electronic version of ADM that would guide users to the needed information and also the ability to perform many of the calculations needed to check the conformance of aluminum structural members with the design specifications.

Experienced developer

The Aluminum Association contracted with Desktop Engineering Int’l Inc. (DEI), Woodcliff Lake, New Jersey, for assistance in this project. DEI is the company that pioneered the concept of the computerized engineering handbook and has developed some of the best examples of this technology. These include The Desktop Engineer, a Windows-based program that provides answers to over 5,000 structural and mechanical engineering problems found in over 100 reference manuals. DEI has also developed products for other industries that provide quick access to design information and automate design procedures.

The Aluminum Design System

The resulting ADS program contains the following applications: 1) ADS Control Center, 2) Aluminum Design Manual, 3) Material Manager, 4) Section Manager, 5) Thin-Walled Section Analysis, 6) Parametric Study, 7) Conformance Check, 8) The Desktop Engineer, and 9) Unit Conversion. The ADS Control Center is the gateway to all the applications in the Aluminum Design System. All the applications in ADS are launched from the Control Center. The Aluminum Design Manual displays the specifications, tables, equations, figures, and other information contained in the paper manual through the use of navigation (hyperlinks) and query (search) features.

Material Manager

The Material Manager is used to locate, view, create and edit material properties for use in ADS. In addition, an ADS default material can be set in the Material Manager. Three types of Material Databases are available in Material Manager - ADS Design, ADS Reference and User Defined. The ADS Design Database contains many of the tables from the Aluminum Design Manual including: 1) Minimum Mechanical Properties for Aluminum Alloys, 2) Minimum Mechanical Properties for Welded Aluminum Alloys, 3) Comparative Characteristics and Applications, and 4) Foreign Alloy Designations and Similar AA Alloys. The ADS Reference Database contains materials that are in the last two tables mentioned that do not have associated values shown in the first two tables mentioned above. User defined material property databases (for example, for proprietary alloys) can also be created and edited. User defined properties can be input one at a time using the edit feature or in mass using the import feature.

Section Manager

The Section Manager is used to locate, view, calculate and edit section properties for use in ADS. In addition, an ADS default section can be set in Section Manager. Four types of cross section databases are available in Section Manager - Channels, I-Beams, Pipes and User Defined Sections. Three types of section property analyses can be started from Section Manager - Common Cross Sections, Common Solids and Thin Walled Sections. Section property results from these applications can be displayed within the Section Manager. Common Cross Sections include 29 different common shapes such as angles, tees, zees, I beams with equal or unequal flanges, rectangles, hollow rectangles, circles, hollow circles, C sections, and hat sections.

Thin Walled Sections

The Thin Walled Sections (TWS) application calculates geometric section properties for arbitrary thin-walled sections. Thin Walled Sections calculates nominal section properties and effective section properties. The effective section properties are computed based on user-specified loads and design method. Thin Walled Sections utilizes the "linear" or "midline" method for section modeling and analysis by which the material of the section is considered to be concentrated along the centerline of straight or curved line elements. A cross section in TWS can consist of three kinds of entities: lines, arcs and welds.

Thin Walled Sections calculates 39 nominal properties for a section without a discontinuity. If a discontinuity is found in the cross section, Thin Walled Sections does not calculate the torsional properties and only 27 properties are calculated. The nominal properties Thin Walled Sections calculates can be divided into two categories:

• General Nominal Properties (27)

• Torsional Properties (12)

Thin Walled Sections calculates 20 effective properties of the effective cross section under specified loads based on the user specified design method. The design method can be the Allowable Stress Design of Buildings, Allowable Stress Design of Bridges, or the Load and Resistance Factor Design. The specified loads have three components - axial load, minor axis moment and major axis moment.

Parametric studies

The Parametric Study application provides the capability to perform parametric studies of equations provided in the Allowable Stress Design and LRFD parts of the Aluminum Design Manual.

The analysis results are shown in two ways - in a table and graphically. This enables the user to study the effect of changing a variable in an equation instantly over a range of possible values.

Conformance Check

The Conformance Check application provides the capability to check whether a member will satisfy the specifications set in the Allowable Stress Design or LRFD sections of the Aluminum Design Manual. This is the heart of ADS – the user inputs loads and member geometry, and the Conformance Check calculates the ratio of computed stress to design stress, even taking into account the effects of welds, web stiffeners, and combined stresses, for example. Member cross sections may be any of the common plane sections described in the Section Manager.

To perform a conformance check analysis, the user clicks the File/New option in the pull-down menu or the New Analysis icon on the toolbar. The Inputs window is divided into nine tabs: 1) Member Definition, 2) Loads, 3) Member Geometry, 4) Material, 5) Cross Section, 6) Lateral Buckling, 7) Welding, 8) Analysis Options, and 9) Additional Analyses. The user clicks on the desired tab name and then enters data into the input fields. In Material and Cross Section tabs, the Modify button is used to change the material or the cross section. Then, the user clicks the Analysis/Solve option in the pull-down menu or clicks Solve icon on the toolbar.

The program performs input error checks and displays an error message if an error is found. If no error is found, the analysis results are shown in the results window. You can review results in the Results window by clicking on any of the eleven tabs that group the results. By clicking the Analysis/Redo option in the pull-down menu or the Redo icon on the toolbar the user can close the Results Window and return to the input window. Then data can be modified for the next analysis.

Summary