Welding of precipitation-hardening stainless steels

Welding of precipitation hardening stainless steel

Long-Term Evaluation of the Acoustic Emission Weld Monitor

The Kentucky Transportation Research Program conducted an extended 10- month evaluation of the Acoustic Emission Weld Monitor (AEWM) in a bridge fabrication shop. That device was used to detect welding flaws during typical production of butt-welds on flanges and webs used in steel bridges. A total of 153 welds were monitored. AEWM test results were compared with visual inspection and double- blind results of conventional nondestructive testing routinely conducted on the welds. The AEWM did not miss any flaws detected visually or by nondestructive testing. Three AEWM flaw indications were confirmed by conventional nondestructive testing (radiography). A large number of AEWM indications were not related to any detected flaws (228 of 263 indications). Those were attributed to AE noise that occurs away from the weld and small flaws that were either missed or overlooked by visual and nondestructive inspection or were removed prior to inspection by normal fabrication procedures. The AEWM has shown the sensitivity to detect AWS code-rejectable defects. In part, the high number of overcalls was caused by use of excessive system sensitivity. Due to the success of the unit in detecting flaws, further development is warranted. Specific recommendations for further research are provided

Research reports: 1990 NASA/ASEE Summer Faculty Fellowship Program

Reports on the research projects performed under the NASA/ASEE Summer Faculty Fellowship Program are presented. The program was conducted by The University of Alabama and MSFC during the period from June 4, 1990 through August 10, 1990. Some of the topics covered include: (1) Space Shuttles; (2) Space Station Freedom; (3) information systems; (4) materials and processes; (4) Space Shuttle main engine; (5) aerospace sciences; (6) mathematical models; (7) mission operations; (8) systems analysis and integration; (9) systems control; (10) structures and dynamics; (11) aerospace safety; and (12) remote sensin

Nonterrestrial utilization of materials: Automated space manufacturing facility

Four areas related to the nonterrestrial use of materials are included: (1) material resources needed for feedstock in an orbital manufacturing facility, (2) required initial components of a nonterrestrial manufacturing facility, (3) growth and productive capability of such a facility, and (4) automation and robotics requirements of the facility

A Corrosion Control Manual for Rail Rapid Transit

This manual addresses corrosion problems in the design, contruction, and maintenance of rapid transit systems. Design and maintenance solutions are provided for each problem covered. The scope encompasses all facilities of urban rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. The types of corrosion and their causes as well as rapid transit properties are described. Corrosion control committees, and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual are listed. A bibliography of papers and excerpts of reports is provided and a glossary of frequently used terms is included

Design and motion planning of body-in-white assembly cells

This paper proposes a method for the automatic and simultaneous identification of the body-in-white assembly cell design and motion plan. The method solution is based on an iterative algorithm that looks for a global optimum by iteratively identifying the optimum of three sub-problems. These sub-problems concern system layout design and motion planning for single and multi-robot systems, while collision detection is addressed. The sub-problems are handled through ad-hoc developed Mixed Integer Programming (MIP) models. The proposed solution overcomes the limitations of the current design and motion plan approaches. In fact, the design of body-in-white assembly cell and the robot motion planning are two time-expensive and interconnected activities, up to now generally managed from different human operators. The resolution of these two activities as non-interrelated could lead to an increase of the engineer-to-order time and a reduction of the solution quality. Thus, a test bed is described in order to prove the applicability of the approach

Foam Wars II

The team producing Foam Wars II consists of three Mechanical Engineering students and five Kinesiology students (three the first two quarters and two the last quarter) at California Polytechnic State University, San Luis Obispo. The project is the second iteration of Foam Wars as a senior project at Cal Poly, sponsored by Dr. Kevin Taylor under the National Science Foundation grant. Persons with disabilities often feel limited when it comes to recreational activities and Foam Wars would provide them with an outlet to interact and engage themselves in a group setting. The game consists of various wheelchair attachments that would pit two teams of five players against each other, where the objective is to score points by launching foam balls into stationary targets placed around a typical regulation basketball court. The goal of the project is not only to improve upon the previous hardware, but to redesign and refresh the whole game to be more engaging and inclusive for its participants. This document will detail the rules of the game and follow the development of the necessary hardware to implement them

SIMAID: a rapid development methodology for the design of acyclic, bufferless, multi-process and mixed model agile production facilities for spaceframe vehicles

The facility layout problem (FL) is a non-linear, NP-complete problem whose complexity is derived from the vast solution space generated by multiple variables and interdependent factors. For reconfigurable, agile facilities the problem is compounded by parallelism (simultaneity of operations) and scheduling issues. Previous work has either concentrated on conventional (linear or branched) facility layout design, or has not considered the issues of agile, reconfigurable facilities and scheduling. This work is the first comprehensive methodology incorporating the design and scheduling of parallel cellular facilities for the purpose of easy and rapid reconfiguration in the increasingly demanding world of agile manufacturing. A novel three-stage algorithm is described for the design of acyclic (asynchronous), bufferless, parallel, multi-process and mixed-model production facilities for spaceframe-based vehicles. Data input begins with vehicle part processing and volume requirements from multiple models and includes time, budget and space constraints. The algorithm consists of a powerful combination of a guided cell formation stage, iterative solution improvement searches and design stage scheduling. The improvement iterations utilise a modified (rules-based) Tabu search applied to a constant-flow group technology, while the design stage scheduling is done by the use of genetic algorithms. The objective-based solution optimisation direction is not random but guided, based on measurement criteria from simulation. The end product is the selection and graphic presentation of the best solution out of a database of feasible ones. The case is presented in the form of an executable program and three real world industrial examples are included. The results provide evidence that good solutions can be found to this new type and size of heavily constrained problem within a reasonable amount of time

Coatings for Corrosion Protection: Offshore Oil and Gas Operation Facilities, Marine Pipeline and Ship Structures

This workshop on Coatings for Corrosion Protection: Offshore Oil and Gas Operation Facilities, Marine Pipelines, Ship Structures, and Port Facilities was held on April 14-16, 2004 in Biloxi, Mississippi. This workshop of 150 attendees drew participation by internationally recognized marine coating experts, material specialists, inspection specialists, coating manufacturers, maintenance engineers, and designers. The workshop was crafted to include multiple viewpoints: industrial, academic, environmental, regulatory, standardization, and certification. Keynote and topic papers were presented to establish a current information base for discussions. Six discussion groups addressed specific issues and identified, prioritized, and recommended specific research and development topics for the government and industries to undertake. The recommendations of this workshop offer a clear identification of research and development issues and create a roadmap for achieving them