SYNOPSIS The determination of the torsional stiffness of a ladder frame is investigated and a comparison made between the assumptions of infinite and finite bending stiffness of the members.
A method is proposed for the estimation of the torsion constants of the members of a ladder frame and is shown to give good agreement with measured values. Stress distributions in the cross-members of a ladder frame are also determined.
Finally charts are presented to enable the torsional stiffness and stress distributions to be calculated for ladder frames comprised of channel and I-Section members.
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References
1.
ErzK.‘Uber die durch Unebenheiten der Fahrbahn hervorgerufene Verdrenung von Strassenfahrzeugen’, A.T.Z. No. 4 April, No. 6 June, No. 11 November, No. 12 December, 1957.
2.
TidburyG. H.MarshallP. H.RoachA.H.‘Torsional stiffness of commercial vehicle chassis frames’, The XII FISITA congress, 1968.
3.
CookeC. J.‘Strain energy theory applied to the chassis frame’, Automotive Design Engineering, Vol. 2, 81, September 1964.
4.
packageI.C.L., ‘Analysis of Space Frames’, 1900 Series.
5.
MarshallP. J.‘Torsional stiffness of ladder frames’, (ASAE thesis) Advanced School of Automobile Engineering, Cranfield1965.
6.
HankeM.‘Thin-walled beams in Automobile Engineering’, Automobile (Prague) 1959.
7.
ZaksM. N.‘The state of stress at the joints of twisted vehicle frames’, Proc. NAMI, Vol. 61, 1963.
8.
TimoshenkoS.GoodierJ. N.‘Theory of Elasticity’, McGraw Hill Book Co., New York, 1951.
9.
AladeG. A.‘Structural Analysis of Ladder Frames under Torsion’, Thesis for the degree of Ph.D., University of Leeds, 1974.
10.
TimoshenkoS.GereJ. M.‘Theory of Elastic Stability’, Second edition, McGraw Hill, New York, 1961.
11.
MegsonT. H. G.‘Aircraft Structures for Engineering Students’, Edward Arnold, London, 1972.
12.
PAFEC 70+ Manual for the Program for Automatic Finite Element Calculations. University of Nottingham, August, 1972.
13.
MegsonT. H. G.‘Extension of the Wagner Torsion Bending Theory to allow for General Systems of Loading’, The Aeronautical Quarterly, Vol. XXVI, August, 1975.
14.
TidburyG. H.The torsional stiffness of an open section thin walled beam in terms of bimoments and the generalization of partial warping inhibition boundary conditions’. Science and Motor Vehicles Conference, UVMV, Belgrade, 1975.
15.
ZaksM. N.NAMI Proceedings, No. 61, 1963, (in Russian).
