Search NASA⌕ Search

Engineering topics

Masubuchi, K.

Publications and source records attributed to Masubuchi, K..

17 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Fundamentals and advances in the development of remote welding fabrication systems

Operational and man-machine issues for welding underwater, in outer space, and at other remote sites are investigated, and recent process developments are described. Probable remote welding missions are classified, and the essential characteristics of fundamental remote welding tasks are analyzed. Various possible operational modes for remote welding fabrication are identified, and appropriate roles for humans and machines are suggested. Human operator performance in remote welding fabrication tasks is discussed, and recent advances in the development of remote welding systems are described, including packaged welding systems, stud welding systems, remotely operated welding systems, and vision-aided remote robotic welding and autonomous welding systems.

Agapakis, J. E.↗
NASA NTRS1985

Feasibility of remotely manipulated welding in space: A step in the development of novel joining technologies

A six month research program entitled Feasibility of Remotely Manipulated Welding in Space - A Step in the Development of Novel Joining Technologies is performed at the Massachusetts Institute of Technology for the Office of Space Science and Applications, NASA, under Contract No. NASW-3740. The work is performed as a part of the Innovative Utilization of the Space Station Program. The final report from M.I.T. was issued in September 1983. This paper presents a summary of the work performed under this contract. The objective of this research program is to initiate research for the development of packaged, remotely controlled welding systems for space construction and repair. The research effort includes the following tasks: (1) identification of probable joining tasks in space; (2) identification of required levels of automation in space welding tasks; (3) development of novel space welding concepts; (4) development of recommended future studies; and (5) preparation of the final report.

Masubuchi, K.↗
NASA NTRS1985

Remotely manipulated and autonomous robotic welding fabrication in space

The results of a NASA sponsored study, performed in order to establish the feasibility of remotely manipulated or unmanned welding fabrication systems for space construction, are presented. Possible space welding fabrication tasks and operational modes are classified and the capabilities and limitations of human operators and machines are outlined. Human performance in remote welding tasks was experimentally tested under the sensing and actuation constraints imposed by remote manipulation in outer space environments. Proposals for the development of space welding technology are made and necessary future R&D efforts are identified. The development of improved visual sensing strategies and computer encoding of the human welding engineering expertise are identified as essential, both for human operator assistance and for autonomous operation in all phases of welding fabrication. Novel uses of machine vision for the determination of the weld joint and bead geometry are proposed, and a prototype of a rule-based expert system is described for the interpretation of the visually detected weld features and defects.

Agapakis, J. E.↗
NASA NTRS1983

Feasibility of remotely manipulated welding in space. A step in the development of novel joining technologies

In order to establish permanent human presence in space technologies of constructing and repairing space stations and other space structures must be developed. Most construction jobs are performed on earth and the fabricated modules will then be delivered to space by the Space Shuttle. Only limited final assembly jobs, which are primarily mechanical fastening, will be performed on site in space. Such fabrication plans, however, limit the designs of these structures, because each module must fit inside the transport vehicle and must withstand launching stresses which are considerably high. Large-scale utilization of space necessitates more extensive construction work on site. Furthermore, continuous operations of space stations and other structures require maintenance and repairs of structural components as well as of tools and equipment on these space structures. Metal joining technologies, and especially high-quality welding, in space need developing.

Masubuchi, K.↗
NASA NTRS1974

Discipline report on thermal analyses of M551, M552, and M553 experiments

Reduced gravity does not significantly affect the thermal histories in the M551 specimen, even if molten metal flow pattern is different from that in terrestrial conditions. Thermal histories corresponding to terrestrial experimental conditions were calculated by use of the computer programs. Heat conduction through brazing alloy (M552 experiment) is improved in the Skylab conditions, because of the increased extent, rate and uniformity of braze spreading in space. Effects of reduced gravity on heat flow in the M553 specimen are insignificant, because convection effects appear instantaneously and conduction is a governing factor on the heat flow.

Muraki, T.↗
NASA NTRS1974

Thermal analysis of M551 experiment for materials processing in space

Heat flow in a disc due to moving heat generated by electron beam was studied analytically. Computer programs based on the finite-element method were developed for the analysis of two and three dimensional mathematical models. The limited experimental data were compared with the analytical results, and factors which had influence on heat flow in the disc were studied. The computer programs were modified to consider the effects of metal melting and solidification as well as radiation. Temperature dependency of thermophysical properties was also considered.

Muraki, T.↗
NASA NTRS1974

Analysis of thermal stresses and metal movement during welding. I - Analytical study

This is the first part of a study of thermal stresses and metal movement during welding. This part discusses analysis of two-dimensional thermal stresses and metal movement during bead-on-plate and butt welding. A finite-element formulation has been derived, based on the variational principle. The formulation includes temperature dependence of material properties as well as the yield criterion.

Muraki, T.↗
NASA NTRS1974

Thermal analysis of M552 experiment for materials processing in space

Analytical and experimental studies made of heat flow in the exothermic brazing unit in the M552 experiment are described. The emphasis of the studies was placed on heat flow in the tube and the sleeve during a period from ignition to the time when the brazing alloy solidifies. Experiments were made of three specimens tested in a ground-based laboratory. Heat flow was determined by thermocouples. The analytical study covered two phases: (1) the effect of reduced gravity on heat flow in the exothermic brazing unit; and (2) the development of analytical models. The major mode of heat transfer was conduction and the effect of gravity was minimal. Good agreements were obtained between experimental and analytical results indicating the soundness of the analytical models.

Muraki, T.↗
NASA NTRS1974

Analysis of thermal stresses and metal movement during welding

Finite element computer programs were developed to determine thermal stresses and metal movement during butt welding of flat plates and bead-on-plate welding along the girth of a cylindrical shell. Circular cylindrical shells of 6061 aluminum alloy were used for the tests. Measurements were made of changes in temperature and thermal strains during the welding process.

Muraki, T.↗
NASA NTRS1974

Welding high-strength aluminum alloys

Handbook has been published which integrates results of 19 research programs involving welding of high-strength aluminum alloys. Book introduces metallurgy and properties of aluminum alloys by discussing commercial alloys and heat treatments. Several current welding processes are reviewed such as gas tungsten-arc welding and gas metal-arc welding.

Parks, P. G.↗
NASA NTRS1973

Analysis of thermal stresses and metal movement during welding

The research is reported concerning the development of a system of mathematical solutions and computer programs for one- and two-dimensional analyses for thermal stresses. Reports presented include: the investigation of thermal stress and buckling of tantalum and columbium sheet; and analysis of two dimensional thermal strains and metal movement during welding.

Muraki, T.↗
NASA NTRS1972

Analysis of thermal stress and metal movement during welding

Objectives of study were: investigation of temperature changes caused by welding arc with analysis of temperature distribution; development of system of mathematical statements describing thermal stresses and plastic strains during welding; and development of system of mathematical solutions and computer programs for one-dimensional analysis.

Andrews, J. B.↗
NASA NTRS1972

Integration of NASA-sponsored studies on aluminum welding

The results are presented of numerous studies relating to aluminum alloy welding. The subjects covered include: (1) effects of porosity on weld joint performance, (2) sources of porosity, (3) weld thermal effects, (4) residual stresses and distortion, and (5) manufacturing process system control.

Masubuchi, K.↗