# HW9 - PROBLEM 2.79 2.79 The plastic block shown 18 bonded...

This preview shows pages 1–2. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: PROBLEM 2.79 2.79 The plastic block shown 18 bonded to a ﬁxed base and to a honzontal I'lgld plate to which a force Pis applied. Knowing that for the plastic used G = 55 ksi, determine the deﬂection of the plate when P = 9 kips. ? Cansr’olev‘ ‘Hle papas‘i'ic bpock. The shear-Wu: Force Carrie) is P = 9:1031L‘ ‘——1> A = (3.5)(5.5)= 19.25 'm‘ 467. 52 PSI. Sheam‘ma 3+V‘aim 7‘ 1' “é— : %% 7 0. 0085006 is 'V = (2.2 3010085006) = 0.0187 in, 2.80 A vibration isolation unit consists of two blocks of hard rubber bonded to plate AB and to rigid supports as shown. For the type and grade of rubber used 2;“ = 220 psi and G = 1800 psi. Knowing that a centric vertical force of magnitude P; 3.2 kips must cause a 0.1 in. vertical deﬂection of the plate AB, determine the smallest allowable dimensions a and b of the block. SOLUTION Consiaicr +Le router Mode on Hm N3 H. I+ Carries a. shearing 4’0»ch equal +9 ~513— Tlde sheqn‘nj 5+ress is f = a2 3 OV‘ required A = -E -——3‘2x‘o : 12727 in“ 22’ - (23(220) 130+ A = (3.0) b - A - - Hence 5 - 3.0 - 2.42 m. "-1 USE b? 1‘”! ha and 2": 220 Pﬁt' Shea-ring S+Nt€n Y 7 g = 1:3): = 0.12222. 11> * B + 7” = 5 #1 l " E HCI’ICQ PROBLEM 2.81 PROBLEM 2.82 2.81 An elastomeric bearing (G = 0.9 MPa) is used to support a bridge girder as shown to provide ﬂexibility during earthquakes. The beam must not displace more than 10 mm when a 22 kN lateral load. is applied as shown. Determine (a) the smallest allowable dimension b, (b) the smallest required thickness 0 if the maximum allowable shearing stress is 420 kPa. SOLUTION 5‘1 Banks \$0.112 P T 227103 N Shear-M») stress 7: “ [+20 VIC:3 Pa -3 . .:_E__ axto‘ _ -3 1. ’Zf- A on A t-ﬁm o52.38lX/O M .— 52.38! x103 m...‘ A 1‘ (200 MM)( .38 3 - 52 1x10 2 262 Mm ‘+é€.é7 x163 2I.Ll mm 2.82 For the elastomeric bearing in Prob. 2.81 with b = 220 mm and a = 30 mm, determine the shearing modulus G and the shear stress rfor a maximum lateral load P = 19 kN and a maximum displacement 6= 12 mm. SOLUTION Shearivﬂ ¥ome P = l‘? x103 N Ana A 1' (ZOO Mh\ ? H‘IXIO: Min-L = Wino“ In" NH}: _ mxlo3 ‘ c. _ ~ 431.8lxtospa A qq’dos = 43! kPa Shequnﬂ si’rafn v: % = —‘3;:—:: ’—'- 0.400 Shearu‘n 3 MOJJIUS N 3 92%.: W = Loaoxlo‘ Pa = L080 M95. 4 ...
View Full Document

{[ snackBarMessage ]}

### Page1 / 2

HW9 - PROBLEM 2.79 2.79 The plastic block shown 18 bonded...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online