1.Account for deformation and the potential for failure when designing systems subjected to forces.
Forces acting on designed artifacts can be significant. All bodies deform under applied forces,
and they can fail if the forces are sufficiently large.
Mechanics of Materials addresses two prime questions:
●How much does a body deform when subjected to forces?
●When will forces applied to a body be large enough to cause the body to fail?
Deformation and failure depend on the forces and on the body’s material, size, and shape.
2.Deformations within acceptable limits-
In most situations,we try to avoid failure and keep deformations within acceptable limits.
If we know the forces under which failure would occur, we can design to avoid failure. Further, a system often needs to remain close to its original shape to function properly. If we can quantify deformations, we can design the system to avoid undesirably large deformation.
3.Desirable deformation -
Deformation is desirable in some situations where it depends predictably on the forces.Some products must deform to carry out their function. They are designed to have a desired relation between the deformation and the acting forces.
For example, such products include pole vaults that flex to temporarily store energy that later propels the vaulter, mountings that accommodate motions of helicopter blades, and support springs that allow for deflection of structural members.
4.Desirable failure -
Occasionally, failure is desirable, if it occurs at a reproducible level of load.
Rarely, we sometimes deliberately want failure to occur when loads reach a predetermined level. In expensive equipment, failure can be disastrous. So, engineers design into the equipment an inexpensive extra part, which fails at a consistent force that is safely less than the main components can tolerate.
For the transmission shaft in a drive train, such a system that protects the shaft is called a torque fuse. Just as an old fashioned electric fuse breaks when the current is too high, the pins in the torque fuse break when the torque is too high.
Forces acting on designed artifacts can be significant. All bodies deform under applied forces,
and they can fail if the forces are sufficiently large.
Mechanics of Materials addresses two prime questions:
●How much does a body deform when subjected to forces?
●When will forces applied to a body be large enough to cause the body to fail?
Deformation and failure depend on the forces and on the body’s material, size, and shape.
2.Deformations within acceptable limits-
In most situations,we try to avoid failure and keep deformations within acceptable limits.
If we know the forces under which failure would occur, we can design to avoid failure. Further, a system often needs to remain close to its original shape to function properly. If we can quantify deformations, we can design the system to avoid undesirably large deformation.
3.Desirable deformation -
Deformation is desirable in some situations where it depends predictably on the forces.Some products must deform to carry out their function. They are designed to have a desired relation between the deformation and the acting forces.
For example, such products include pole vaults that flex to temporarily store energy that later propels the vaulter, mountings that accommodate motions of helicopter blades, and support springs that allow for deflection of structural members.
4.Desirable failure -
Occasionally, failure is desirable, if it occurs at a reproducible level of load.
Rarely, we sometimes deliberately want failure to occur when loads reach a predetermined level. In expensive equipment, failure can be disastrous. So, engineers design into the equipment an inexpensive extra part, which fails at a consistent force that is safely less than the main components can tolerate.
For the transmission shaft in a drive train, such a system that protects the shaft is called a torque fuse. Just as an old fashioned electric fuse breaks when the current is too high, the pins in the torque fuse break when the torque is too high.
No comments:
Post a Comment