howe Posted July 22, 2017 Posted July 22, 2017 Can some one either give me a link of confirm mech props of above. Best I have is Ftu=262 Mpa Fty = 241 Mpa Looking at 47.8 OD x 1.7 wall tube, which I presume is extruded.
djpacro Posted July 23, 2017 Posted July 23, 2017 Try Chapter B2 of Bruhn's book Analysis and design of flight vehicle structures by E.f Bruhn
howe Posted July 23, 2017 Author Posted July 23, 2017 Try Chapter B2 of Bruhn's book Analysis and design of flight vehicle structures by E.f Bruhn Thanks DJP looks like a lot of good info there, will go searching.
M61A1 Posted July 24, 2017 Posted July 24, 2017 6061-T6 for aviation is drawn tube, not extruded. You may have problems if you extruded tube is seamed. Extruded Aluminum Extruded aluminum is made by heating the aluminum and forcing it through a die. What comes out on the other side is the shape of the final product. To visualize the process, imagine pushing a ball of clay through a circle punched with holes. What comes out on the other side is a series of spaghetti-like strands. The shape of the die determines what the final product will look like. For example, an "I" shaped die creates aluminum I-beams. After the product comes out of the die, it is cooled and then stretched to remove any twisting that occurs during the cooling process. As it hardens, extruded aluminum becomes stronger. The hardening process can take place at room temperature, but since that can be time consuming, most manufacturers employ heated rooms to temper the aluminum quickly. Extruded Aluminum Tubing There are two types of structural tubing made by the extrusion process. In the first one, the aluminum tube is split and then resealed using high temperature, pressure and metallurgical welds. The seam created during this process is sometimes visible to the naked eye. Tubing made this way is not suitable for transporting gases or liquids under extreme pressure as there is a risk of the seam splitting. In the second process, the tube is produced by pushing a hollow billet through a die. Because this tube does not have a seam, it can safely be used to transport or store pressurized gases and liquids. Drawn Aluminum The main difference between extruded and drawn aluminum is the way the aluminum is shaped by the die. While extruded aluminum is pushed through a die to obtain its desired shape, drawn aluminum is pushed into a mold. The aluminum is stretched out into the mold, undergoing what is called plastic deformation. Determining the flexibility of the aluminum, or its plasticity, is a critical part of the process because the aluminum cannot be stretched to the point where it becomes brittle or tears. Drawn aluminum typically makes cans, pots and other circular objects. Drawn Structural Tubing In the beginning, a drawn structural tube goes through the same process as an extruded tube. However, where an extruded tube is cooled after it is forced through the die, the drawn tube is sent through a second die. This process is called cold drawing or cold working, and it is here that the final dimensions of the product are determined. A drawn tube is just as suitable for transporting gases or liquids under pressure as a seamless extruded tube. Show comments 1
Head in the clouds Posted July 25, 2017 Posted July 25, 2017 Yup, my good friend howe doesn't mention how he intends to use this 'extruded' tube. I tried to find a source of 47.8x1.7 and couldn't ... it's close to a 6061T6 size but not quite ... In pure tension or compression an extruded tube exhibits reasonably close values to its supposed tensile strengths but if it's to be used in a cantilever/bend/flex situation, for a spar perhaps, then extruded is not predictable so only DoM (drawn over mandrel) product should be used. In this case, IIRC, DoM is about 2.5x stronger.
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