What is the origin of “crash at someone’s place”?

Solution 1:

According to Green’s Dictionary of Slang “crash at/with” is a variant of “crash (out)” meaning to sleep, to collapse exhausted (1945) originally from the RN slang expression “crash the swede.”

crash (out) v. (originally from Royal Navy slang crash the swede, to sleep; as such it migrated first to Australia then to US and finally back to UK)

2. to stay, to lodge, to board; thus crash at, to stay at; crash with, to stay with.

1968 - [US] N. von Hoffman We are the People Our Parents Warned Us Against 275: I don’t have a place to crash.

1970 - [US] Time 30 Mar. 10: A transient arrives looking for a place to crash.

1981 - [US] A.K. Shulman On the Stroll 226: I don’t have any place to stay and I wondered [...] if I could crash with you for a little while.

1999 - [UK] Indep. on Sun. Rev. 10 Oct. 67: He crashed at my apartment for a while.

From “A Dictionary of Slang and Unconventional English” by Eric Partridge: Crash the (one’s) swede:

to get one’s head down on the pillow: Royal Navy, lowerdeck; since ca. 1920:

• Weekly Telegraph (25 Oct. 1944). A more violent version of the earlier army set the swede down. c.f. also the later crash down or simply crash.

Solution 2:

Merriam Webster online gives two definitions of the term crash pad namely

1: protective padding (as on the inside of an automobile or a tank)

2: a place to stay temporarily

The same dictionary also gives the first known use of "crash pad" as being from 1939 and in the sense of 1: above. That is the literal, physical piece of protective padding.

I suspect that the original use of "crash pad" to mean an informal sleeping place was originally derived either from the use of crash pads inside or removed from parked or wrecked tanks in war zones as makeshift mattresses or from a perceived similarity between makeshift mattresses and actual crash pads.

Once the metaphorical use of "crash pad" had become established the back development of the slang verb "to crash" meaning to sleep informally using a piece of floor or a makeshift mattress could well have been rapid, particularly among demobbed WW2 veterans returning to civilian life.

The development of "crash pad" to mean a small second home in a city for a rich person and, therefore, "pad" for the home (often a squat) for beatniks, hippies and other members of sub cultures could also derive from this.

There is also a possibility that "pad" for a small home could be influenced by the more formal "pied à terre" (literally "foot to the ground") for a small second home.

I have spent a long time talking about the derivation of "crash pad" and "pad" to mean more or less informal living accommodation because it seems to me that the most likely origin of the verb "to crash" meaning "to sleep somewhere informally" is intimately connected with "crash pad", "pad" and, possibly, "pied à terre"

I have very little proof for this but I am posting it as an answer rather than a comment because I needed the space to expound my argument. If anyone down votes it I would urge them to place a counter argument or refutation in a comment.