Council study proposes programs
to enhance design of ships
How can engineers design better ships? A committee of the National Research Council has been tackling the question in a multi-year project. The panel, called the Interagency Ship Structure Committee, has issued its latest findings and proposals for the coming fiscal year. According to its report: Tools for the design of ship structure are varied and sometimes fragmented. The output of one computer program cannot be used directly as part of the input to another. Further, the input and output data do not relate to the database used in ship construction. Common interfaces are needed. Some structural failures stem from errors in design procedures. For example, fatigue analysis was not required following the lifting of allowable operating stresses. Human error is an important component of uncertainty, but it is not an explicit factor in probability-based codes. The committee has launched a demonstration project. It will compare a hull girder designed using present conventional rules of the American Bureau of Shipping with a design that uses probability-based procedures. To foster interest, the committee suggests creation of a "Student Design Competition for Innovative Producible Marine Structures."
New design competition linked to 'supercar' initiative
The Department of Energy wants to add the brainpower of college students to the national effort to build a highly efficient automobile. Next year the agency will begin sponsoring a FutureCar Challenge. It is to be an adjunct to the Partnership for a New Generation of Vehicles (PNGV). Aim of the PNGV is to build a mid-size production vehicle that will get up to three times the fuel efficiency of a present version while keeping the same levels of performance. The initial FutureCar Challenge will be limited to 12-18 college teams in 1996. They will design and build systems that work toward the PNGV goal. Plans are to include a design review evaluation, conducted by PNGV government and industry participants, as well as a mid-distance road rally.
'High power' photodiodes improve remote connections
A "high power" photodiode dramatically improves the gain, noise, and dynamic range of optical links. Ortel Corporation, of Alhambra, CA, showed the device at the Armed Forces Communications and Electronics Association conference in Washington, DC. Ortel says its creation can accept 750% higher optical input powers than typical photodiodes without damage or distortion. The improvements are possible because the new photodiode accepts optical powers of up to 15 mW rather than the approximate 2 mW for most photodiodes. Higher optical power results in higher radio frequency (RF) gain, higher RF power, and higher dynamic range. Optical links are used extensively to remote RF and microwave antennas.
Panel urges spacecraft engineers to consider orbital debris
Another fresh report from the National Research Council warns of the growing hazard to spacecraft posed by man-made debris. It beseeches spacecraft designers to pay more attention to the problem. Much research has gone into ways to protect craft against orbital debris, the report says, but results are not widely known. It recommends creation and distribution of a guide for designers. The guide would discuss shielding of critical components of spacecraft and the building of backups into key systems. Major contributors to debris have been explosions in space. "Passivation" can be applied to numerous spacecraft subsystems. For example, spacecraft batteries are sources of stored energy believed responsible for some breakups. Engineers, the report continues, can design a system that ensures that the batteries will be left discharged at the end of the spacecraft's functional lifetime. Designers should beware of the unintentional release of surface materials, including paint and other thermal control materials. New surface materials that minimize release of small particles during launch and operation are needed. Because of the long lead time required to develop and qualify new space hardware, the report concludes, it is necessary to begin setting standards now.
Still got CAD fright? Software aims to boost learning curve
Drafix QuickCAD is a new CAD program built to appeal to both computer dummies and sophisticates. It even can be picked up fast by those with little experience at a drafting board. Softdesk Retail Products, of Kansas City, MO, demonstrated its latest creation in Arlington, VA. QuickCAD, which runs on Microsoft Windows®, lets you select the toolset that matches your experience level. It uses international skiing symbols--a green circle for beginner, a blue square for advanced, and a black diamond for expert. The package includes a CD-ROM with hundreds of sample drawings and general symbols --mechanical, electrical, and architectural.