13
a stress concentration zone is formed at the pushing load
on the applying side, with the maximum stress reaching
29 MPa. The concentration zone gradually diffuses around
and gradually decreases, and the stress reaches 2.5 MPa
at the contact point with the second support. The over-
all stress of the lower support is small, indicating that the
dynamic load impact is not transmitted to the lower sup-
port at this time, and the impact on the lower support is
small. At this time, the lower support is less likely to slide
and lose stability. When the impact load is transmitted by
the upper support at 80 ms, and the load is not balanced,
the upper support is prone to toppling and losing stability.
Between 80 and 100 ms, the maximum principal stress of
the lower support decreases from 7.5 MPa to 2.5 MPa, so
the lower support is not easy to lose stability. At 100 ms, the
upper support is still affected by the side push load, and the
maximum main stress at the hinged joint between the top
beam and the protection plate reaches 29 MPa, which eas-
ily leads to the tipping instability of the support, and leads
to the serial instability of the support group.
It can be seen that under the three kinds of impact, the
load is transmitted to the four sides along the dynamic load
position, and the stress concentration occurs in the position
where multiple components of the hydraulic support are
hinged, and the dynamic load in this position cannot be
rapidly transmitted and diffused, which is easy to cause the
instability of the support. The three kinds of impact loads
show asymmetric load characteristics, and the load of the
lower bracket is smaller than that of the upper bracket.
The load at the bottom of all the columns is almost
greater than that in the middle and upper parts. In order to
reduce the impact load transfer effect of the column on the
bottom plate or base, it is necessary to prevent the instabil-
ity of the bracket due to the fall of the base, and the col-
umn is not easy to slide and become unstable. The above
research conclusions are basically consistent with the results
of physical similar simulation experiments.
Combined with the above research conclusions, the
following improvement measures are proposed for the sta-
bility control of the stent:
1. Increase the contact area between the support and
the bottom plate to reduce the damage probability
to the bottom plate to prevent the subsidence of
the working face support, it is usually possible to
design the support base and adjust the stress state
of the base by reducing the specific pressure of the
Figure 22. Stress evolution law of support under different impact
a stress concentration zone is formed at the pushing load
on the applying side, with the maximum stress reaching
29 MPa. The concentration zone gradually diffuses around
and gradually decreases, and the stress reaches 2.5 MPa
at the contact point with the second support. The over-
all stress of the lower support is small, indicating that the
dynamic load impact is not transmitted to the lower sup-
port at this time, and the impact on the lower support is
small. At this time, the lower support is less likely to slide
and lose stability. When the impact load is transmitted by
the upper support at 80 ms, and the load is not balanced,
the upper support is prone to toppling and losing stability.
Between 80 and 100 ms, the maximum principal stress of
the lower support decreases from 7.5 MPa to 2.5 MPa, so
the lower support is not easy to lose stability. At 100 ms, the
upper support is still affected by the side push load, and the
maximum main stress at the hinged joint between the top
beam and the protection plate reaches 29 MPa, which eas-
ily leads to the tipping instability of the support, and leads
to the serial instability of the support group.
It can be seen that under the three kinds of impact, the
load is transmitted to the four sides along the dynamic load
position, and the stress concentration occurs in the position
where multiple components of the hydraulic support are
hinged, and the dynamic load in this position cannot be
rapidly transmitted and diffused, which is easy to cause the
instability of the support. The three kinds of impact loads
show asymmetric load characteristics, and the load of the
lower bracket is smaller than that of the upper bracket.
The load at the bottom of all the columns is almost
greater than that in the middle and upper parts. In order to
reduce the impact load transfer effect of the column on the
bottom plate or base, it is necessary to prevent the instabil-
ity of the bracket due to the fall of the base, and the col-
umn is not easy to slide and become unstable. The above
research conclusions are basically consistent with the results
of physical similar simulation experiments.
Combined with the above research conclusions, the
following improvement measures are proposed for the sta-
bility control of the stent:
1. Increase the contact area between the support and
the bottom plate to reduce the damage probability
to the bottom plate to prevent the subsidence of
the working face support, it is usually possible to
design the support base and adjust the stress state
of the base by reducing the specific pressure of the
Figure 22. Stress evolution law of support under different impact