What incidents and metaphor in chapter 11 of All Quiet on the Western Front show that the men's nerves are frayed?

By the end of Chapter 11 of All Quiet on the
Western Front, which takes place in the summer of 1918, it is clear that the
German army is losing the war. The men are becoming nervous and losing their will to
fight. 

Paul, the narrator, says of this
time:

"The
summer of 1918 is the most bloody and the most terrible. The days stand like angels in
blue and gold, incomprehensible, above the ring of annihilation. Every man here knows
that we are losing the war" (page
284). 

The metaphor (a
simile) here is that days are like angels, standing above the horrors and death of war
and not comprehending its carnage. 

At this point in the
novel, the German army does not have enough soldiers or ammunition to mount another
offensive. Before the summer, some soldiers try to desert, such as Detering, who
collected cherry blossoms and then tried to escape the army and head back to Germany
(page 275-277). The opposing forces, composed of British and Americans, have much
greater supplies and numbers of troops. Paul says, "For one hungry, wretched German
soldier come five of the enemy, fresh and fit. For one German army loaf there are fifty
tins of canned beef over there" (page 286). The German soldiers do not have the
necessary supplies to fight.

Paul and the other men hope
for peace. He says, "Wild, tormenting rumors of an armistice and peace are in the air,
they lay hold on our hearts and make the return to the front harder than ever" (page
285). The prospect of peace makes the men's nerves frayed because they are so close to
the end of the war and know that if they die, it will be in vain. Their deaths at this
point in the war will be pointless. 

Though there is talk
of peace and an armistice, the soldiers have to continue fighting. Another metaphor in
this chapter is that of the hope of peace. The author writes of "the breath of hope that
sweeps over the scorched fields" (page 285). Hope is like the warm summer wind that
entices the men to think and pray that peace is near, but, like the wind itself, peace
is elusive.