On 3 February 1998, an EA-6B Prowler, an electronic warfare (anti-radar) aircraft belonging to the...
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On 3 February 1998 , an EA-6B Prowler , an electronic warfare (anti-radar) aircraft belonging to the U.S. Marines struck a cable supporting a gondola in Cavalese. The cable was severed and 20 people in the cabin plunged over 80 metres to their deaths. The plane had wing and tail damage but was able to return to the base. Those killed, 19 passengers and one operator, were all of European nationalities: eight Germans (one of whom lived in Austria), five Belgians, three Italians, two Poles, one
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From Statics 1 Equation and two unknowns! Since the forces are statically indeterminate we need an additional relationship. We will determine a kinematic condition. For equilibrium the relative displacement must be equal to 0 Assuming AE is constant At C forces balance and no elongation
Transcript of On 3 February 1998, an EA-6B Prowler, an electronic warfare (anti-radar) aircraft belonging to the...
On 3 February 1998, an EA-6B Prowler, an electronic warfare (anti-radar) aircraft belonging to the U.S. Marines struck a cable supporting a gondola in Cavalese. The
cable was severed and 20 people in the cabin plunged over 80 metres to their deaths. The plane had wing and tail damage but was able to return to the base.
Those killed, 19 passengers and one operator, were all of European nationalities: eight Germans (one of whom lived in Austria), five Belgians, three Italians, two Poles,
one Austrian and one Dutch.
'Too low and too fast' Prosecutors say Capt Ashby flew the
four-man jet below the 1,000-foot (300-metre) minimum altitude
specified by the US Air Force and Marines. They say he also exceeded the 517 mph (832 kph) speed limit.
His lawyers say instruments in the jet were misleading and say he was being used as a scapegoat by the
Marine Corps. A map issued by the US Government did not show the cable car wires. they
also allege. Several of the victims' families are seeking compensation from the US
Government.
0 PFF AB
From Statics
1 Equation and two unknowns!
Since the forces are statically indeterminate we need an additional relationship. We will determine a kinematic condition. For equilibrium the relative displacement must be equal to 0
0/ BA 0/ AELF
AELF
AEFL BCBACA
BA
Assuming AE is constant
0 BCBACA LFLF 0)( BCAACA LFPLF
At C forces balance and no elongation
LLPF CB
A
LLPF AC
B
Force Method for statically indeterminate axial loading
Reaction forces cannot be determined using statics alone.
Choose one support to be redundant (we will choose B).
By superposition I=IIa+IIb
I
0 BP
AEPLAC
P
AELFB
B
LPLF
AELF
AEPL AC
BBAC 0
00
AAC
AAC F
LLLPPF
LLP
From statics
LPLF BC
A
Since L=LAC+LBC
Two approaches to solve the same problem.
Thermal Stress
In practice thermal stresses are very common. E.g. bridge decks contain expansion joints to reduce these effects (left).
TLT Where alpha is the linear co-efficient of thermal expansion
L
T Tdx0
If temperature varies along the length of a bar.
Three bars made of different materials are connected together and placed between two walls when the temperature is T1=12°C. Determine the force exerted on the (rigid) supports when the temperature becomes T2=18°C. The materials properties and cross-sectional area of each bar are given in the Figure.
