Isogrid
Encyclopedia
An isogrid is a plate with triangular integral stiffening ribs (often called stringers). The stiffeners of an isogrid are generally machined from a single sheet of material with a milling machine, though below 0.004 in. (0.1 millimeter) thickness chemical milling processes must be used. The triangular pattern is very efficient because triangular trusses are very efficient structures. The term isogrid is used because the structure acts like an isotropic material, with equal properties measured in any direction, and grid, referring to the sheet and stiffeners structure.
Metal isogrids (often aluminum), are constructed by milling material from one face of a sheet.
Composite isogrids are rib-skin configurations formed by various manual or automated processes, and can give extremely high strength-weight ratios. Traditionally, the equilateral triangle pattern was used because it was amenable to simplified analysis. Since the equilateral triangle pattern has isotropic strength characteristics (no preferntial direction), it was named isogrid. The traditional equilateral pattern can be abandoned in favor of stiffener patterns optimized to specified loading situations; these structures are referred to as composite grid structures or advanced grid stiffened (AGS) structures.
Isogrid panels form self-stiffened structures where low weight, stiffness, strength and damage tolerance are important, such as in aircraft or space vehicles.
Aerospace isogrid structures include payload shrouds, and boosters which must support the full weight of upper stages and payloads under high G loads.
Some spacecraft and launch vehicles which use isogrid structures include:
The Space Shuttle
lightweight and superlightweight external tanks use an integrally machined stringer system which is not a true isogrid, though it is somewhat similar. Since the structure is arranged at right angles it is considered an "orthogrid" rather than an isogrid with triangular stiffeners of an isogrid.
Isogrids are beginning to be used in consumer products where extremely light weight, strength, and stiffness are important, like tennis rackets.
Metal isogrids (often aluminum), are constructed by milling material from one face of a sheet.
Composite isogrids are rib-skin configurations formed by various manual or automated processes, and can give extremely high strength-weight ratios. Traditionally, the equilateral triangle pattern was used because it was amenable to simplified analysis. Since the equilateral triangle pattern has isotropic strength characteristics (no preferntial direction), it was named isogrid. The traditional equilateral pattern can be abandoned in favor of stiffener patterns optimized to specified loading situations; these structures are referred to as composite grid structures or advanced grid stiffened (AGS) structures.
Isogrid panels form self-stiffened structures where low weight, stiffness, strength and damage tolerance are important, such as in aircraft or space vehicles.
Aerospace isogrid structures include payload shrouds, and boosters which must support the full weight of upper stages and payloads under high G loads.
Some spacecraft and launch vehicles which use isogrid structures include:
- DeltaDelta rocketDelta is a versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. There have been more than 300 Delta rockets launched, with a 95 percent success rate. Two Delta launch systems – Delta II and Delta IV – are in active use...
families - Atlas VAtlas VAtlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...
rocket - SkylabSkylabSkylab was a space station launched and operated by NASA, the space agency of the United States. Skylab orbited the Earth from 1973 to 1979, and included a workshop, a solar observatory, and other systems. It was launched unmanned by a modified Saturn V rocket, with a mass of...
spacestation Orbital Workshop module - CST-100 crew capsule
- DragonDragon (spacecraft)The Dragon is a reusable spacecraft developed by SpaceX, a private space transportation company based in Hawthorne, California. During its unmanned maiden flight in December 2010, it became the first commercially-built and -operated spacecraft to ever be successfully recovered from orbit.The Dragon...
crew capsule - MPCV formerly OrionOrion (spacecraft)Orion is a spacecraft designed by Lockheed Martin for NASA, the space agency of the United States. Orion development began in 2005 as part of the Constellation program, where Orion would fulfill the function of a Crew Exploration Vehicle....
crew capsule
The Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
lightweight and superlightweight external tanks use an integrally machined stringer system which is not a true isogrid, though it is somewhat similar. Since the structure is arranged at right angles it is considered an "orthogrid" rather than an isogrid with triangular stiffeners of an isogrid.
Isogrids are beginning to be used in consumer products where extremely light weight, strength, and stiffness are important, like tennis rackets.