1. The document discusses analyzing truss structures using the stiffness method. It begins by introducing the fundamentals of the stiffness method for truss analysis.
2. It describes how to derive the member stiffness matrix for each truss member, which relates the forces and displacements in the member's local coordinate system.
3. It provides equations to transform between the member's local coordinate system and the global coordinate system of the truss, in order to assemble the overall structure stiffness matrix for the truss.
5. Department of Civil Engineering NPIC
!$>#> m:aRTIsbMElgénbMlas;TI nigkmøaMg
(Displacement and force transformation matrices)
edaysar truss pSMeLIgedayGgát;eRcIn eyIgnwg
begáItviFIsRmab;bMElgkmøaMgkñúgGgát; q nig bMlas;TI d
EdlkMNt;enAkñúgkUGredaentMbn;eGayeTACakUGredaen
skl. edIm,IPaBgayRsYl eyIgnwgBicarNakUGredaen
sklviC¢man x manTisedAeTAsþaM ehIy y manTisedA
eLIgelI. mMurvagG½kSskl x, y nigG½kStMbn; x' , y'
RtUv)ankMNt;eday θ x ehIy θ y dUcbgðajenAkñúgrUbTI
14-3. eyIgnwgeRbI kUsIunUsénmMuTaMgenHenAkñúgkarviPaK
m:aRTIsdUcteTA. eyIgtag λ x = cosθ x ehIy λ y = cosθ y . eKGackMNt;témøCaelxsRmab; λ x
nig λ y y:aggayedayeRbIkMuBüÚT½r enAeBleKkMNt; kUGredaen x, y éncugCit N nigcugq¶ay F rbs;
Ggát;rYcehIy. ]TahrN_ eKmanGgát; NF dUcbgðajenAkñúgrUbTI 14-4. enATIenH kUGredaenrbs; N
nig F KW (x N , y N ) nig (x F , y F ) erogKña . dUcenH
*
xF − x N xF − xN
λ x = cos θ x = = (14-5)
L (x F − xN ) + (yF − y N )
2 2
yF − yN yF − yN
λ y = cos θ y = = (14-6)
L (x F − xN ) + (yF − yN )
2 2
*
Kl;rbs;kUGredaenGacsßitenATINak¾)an eGayEtmanlkçN³gayRsYl. b:uEnþ CaTUeTA vaeRcInsßitenARtg;TItaMgNaEdl
kUGredaenrbs; node TaMgGs;viC¢man dUcbgðajenAkñúgrUbTI 14-4.
karviPaK truss edayeRbIviFIPaBrwgRkaj T.Chhay -468
7. Department of Civil Engineering NPIC
b¤ d = TD (14-8)
⎡λ x λ y 0 0 ⎤
Edl T =⎢ ⎥ (14-9)
⎣ 0 0 λx λ y ⎦
BIkarbMEbkxagelI T bMElgBIbMlas;TI D kñúgkUGredaenskl x, y TaMgbYneGayeTACabMlas;TI d kñúg
kUGredaentMbn; x' cMnYnBIr. dUcenH T Cam:aRTIsbMElgbMlas;TI.
m:aRTIsbMElgkmøaMg³ BicarNakarGnuvtþkmøaMg q eTAelIcugCitrbs;Ggát; cMENkcugq¶ayRtUv)anTb;
N
edaysnøak; ¬rUbTI 14-6a¦. enATIenH bgÁúMkmøaMgsklrbs; q N enARtg; N KW
Q N x = q N cos x Q N y = q N cos θ y
dUcKña RbsinebI q F RtUv)anGnuvtþeTAelIr)ar ¬rUbTI 14-6b¦ bgÁúMkmøaMgsklenARtg; F KW
Q Fx = q F cos θ x Q Fy = q F cos θ y
edayeRbIkUsIunUsR)ab;Tis λ x = cosθ x / λ y = cosθ y smIkarTaMgenHkøayCa
QN x = q N λ x QN y = q N λ y
Q Fx = q F λ x Q Fy = q F λ y
EdleKGacsresrvaCaTRmg;m:aRTIsdUcxageRkam
karviPaK truss edayeRbIviFIPaBrwgRkaj T.Chhay -470
25. Department of Civil Engineering NPIC
kñúgrUbTI 14-12b EdlmanRbB½n§kUGredaenskl x, y enARtg;cugCit N ehIyRbB½n§kUGredaenrbs;
node x' ' , y ' ' enARtg;cugq¶ay F . enAeBlbMlas;TI D ekIteLIg dUcenHBYkvamanbgÁúMtambeNþayG½kS
nImYy²dUcbgðajenAkñúgrUbTI 14-12c enaHbMlas;TItamTis x tambeNþaycugGgát;nImYy²køayCa
d N = D N x cos θ x + D N y cos θ y
d F = DFx '' cos θ x '' + DFy '' cos θ y ''
eKGacsresrsmIkarTaMgenHenAkñúgTRmg;m:aRTIs
⎡ DN x ⎤
⎢ ⎥
⎡ d N ⎤ ⎡λ x λ y 0 0 ⎤ ⎢ DN y ⎥
⎢d ⎥ = ⎢ 0 0 λ λ y '' ⎥ ⎢ DFx '' ⎥
⎣ F⎦ ⎣ x '' ⎦⎢ ⎥
⎢ D Fy '' ⎥
⎣ ⎦
dUcKña kmøaMg q enARtg;cugCit nigcugq¶ayrbs;Ggát; ¬rUbTI 14-12d¦ manbgÁúM Q tambeNþayG½kSskl
Q N x = q N cos θ x Q N y = q N cos θ y
Q Fx '' = q F cos θ x '' Q Fy '' = q F cos θ y ''
EdleKGacsresrCa
⎡ Q N x ⎤ ⎡λ x 0 ⎤
⎢Q ⎥ ⎢ ⎥
⎢ N y ⎥ = ⎢λ y 0 ⎥ ⎡ q N ⎤
⎢Q Fx '' ⎥ ⎢ 0 λ x '' ⎥ ⎢ q F ⎥
⎣ ⎦
⎢ ⎥ ⎢ ⎥
⎢Q Fy '' ⎥ ⎢ 0 λ y '' ⎥
⎣ ⎦ ⎣ ⎦
eKeRbIm:aRTIsbMElgbMlas;TI nigm:aRTIskmøaMgenAkñúgsmIkarxagelIedIm,IbegáItm:aRTIsPaBrwgRkaj
sRmab;Ggát;enAkñúgsßanPaBenH. edayGnuvtþsmIkar 14-15 eyIg)an
k = T T k 'T
⎡λ x 0 ⎤
⎢λ ⎥
k= ⎢ y 0 ⎥ AE ⎡ 1 − 1⎤ ⎡λ x λ y 0 0 ⎤
⎢− 1 1 ⎥ ⎢ 0 0 λ
⎢ 0 λ x '' ⎥ L ⎣ ⎥
⎦⎣ x '' λ y '' ⎦
⎢ ⎥
⎢ 0 λ y '' ⎥
⎣ ⎦
edayKNnam:aRTIsxagelI eyIgTTYl)an
⎡ λ2 x λ x λ y − λ x λ x '' − λ x λ y '' ⎤
⎢ ⎥
AE ⎢ λ x λ y λ2 y − λ y λ x '' − λ y λ y '' ⎥
k= (14-24)
L ⎢ − λ x λ x '' − λ y λ x '' λ2 '' λ x '' λ y '' ⎥
⎢ x ⎥
⎢− λ x λ y '' − λ y λ y '' λ x '' λ y '' λ2 '' ⎥
⎣ y ⎦
bnÞab;mkeKGaceRbIm:aRTIsPaBrwgRkajsRmab;Ggát;nImYy²EdlRtUvtP¢ab;eTAnwgTMrkl;EdleRTt ehIy
dMeNIrkarpÁúMm:aRTIsedIm,IbegáItm:aRTIsPaBrwgRkajrcnasm<½n§GnuvtþtamdMeNIrkarbTdæan. ]TahrN_xag
karviPaK truss edayeRbIviFIPaBrwgRkaj T.Chhay -488