Crumpling


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Crumpling

 

in strength of materials, a localized compressive stress, accompanied, as a rule, by permanent deformation (pressing down) of the material. Crumpling occurs in joints (bolted, riveted, key) in locations of structural supports, and in contact zones of compressed components.

The magnitude of crumpling stress in structures is usually kept below the allowable crumpling stress. This allowable stress is determined by the character of the surfaces in contact, the properties of the structural material, and the orientation of this material with respect to applied loads (for instance, with wood, parallel or perpendicular to the grain). Various design features aimed at reducing crumpling stresses and, more important, permanent deformation distribute the compressive stress over a large area with the aid of, for example, washers, liners, and pads. One of the most effective means for reducing deformation is the use of special inserts and fillers in the contact zones made of materials that are stronger than the structural material.

L. V. KASAB’IAN

References in periodicals archive ?
We have developed a method to solve this problem and control the crumpling and unfolding of large-area graphene films," Zhao said.
In this way, the crumpling and unfolding of large-area, atomic-thick graphene can be controlled by simply stretching and relaxing a rubber film, even by hands," Zhao said.
For example, we can tune the graphene from being transparent to opaque by crumpling it, and tune it back by unfolding it," said Jianfeng Zang, a postdoctoral fellow in Zhao's group and the first author of the paper.
The crumpling and unfolding of graphene allows large deformation of the artificial muscle," Zang said.
To see how it might work, Heatherwick's studio devised a bespoke crumpling device, like a heavy Victorian mangle, its roller kinkily studded with rubber nodules.
Researchers are now recording and characterizing the sounds of crumpling to obtain insights into how energy is distributed and dissipated in materials under stress.
Crumpling a sheet of paper into a tight ball causes some regions to become strongly creased, creating a network of narrow ridges and sharp peaks.
To investigate the energy involved in crumpling, physicist Thomas A.
Because sheets of different materials-whether paper, mylar, or metal-display similar ridges, the basic crumpling process must be similar in these materials.
A lab near Paris is expected to finish them in September or October - more than a year after the car smashed into a pillar in the Alma traffic tunnel, crumpling into a tangle of smoking metal.
But various scientists over the last 25 years have noted signs that the lithosphere was crumpling south of India - a region far from the recognized boundaries of the Indo-Australian plate.
Both front air bags of the white stretch limo deployed when the car careened off southbound Woodward into the grassy median of the divided road and hit a tree, crumpling the front end.