Impact fatigue loading - импульсивное нагружение усталостного типа
N 22
SHOCK AND
IMPACT PROPERTIES (III)
Characteristics
of the structure.
The damage produced by shock loading is naturally dependent
upon the characteristics of the structure. If the time of
application of the load is short compared to the lowest natural
frequency of vibration of the structure or machine, an impact
load is produced, whereas if the time of load application is
long, the load is considered to be static. In most cases, if
the time of load application is less than one-half the lowest
natural frequency of vibration, the load is definitely
considered to be a shock or impact load. If this time interval
is greater than three time the natural frequency, the load
is generally considered to be a static load. The time of
loading referred to above is the time required to increase
the load from zero to a maximum value. For dynamic shock
loads the shape of the load-time curve, particularly the
steepness of its rise or fall is important. The impulse
(equal to the area under the load-time curve) is a basic
consideration in design. On the other hand, for slow
loading, the shape of the load-time curve is unimportant
since the maximum load is the major design factor.
Notes
:
shock
loading - ударная
нагрузка
Impact loading - импульсивная нагрузка
load-time
curve
- нагрузочно-временная кривая
