A frame of two arms of equal length L is shown in the adjacent

A frame of two arms of equal length L is shown in the adjacent figure. The flexural rigidity of each arm of the frame is El. The vertical deflection at the point of application of load P is

EI	d²y	= - M_x
	dx²

or M_x = – P (L–x)

∴ EI	d²y	= P (L–x)
	dx²

Integrating two times and
puting x = L, we get

y =	PL³
	3EI

U =	P²L³	+	P²L³	=	4P²L³
	2EI		6EI		6EI

∴	1	× P × deflection =	4P²L³
	2		6EI

or Deflection =	4P²L³
	6EI