SHEAR CENTER LOCATOR
Field of Invention
The present product relates to the development of a Shear center locating apparatus that has an innovative
design. The apparatus has been tested successfully to obtain the shear center of very thin walled beam
sections with symmetric or un-symmetric loading conditions. The apparatus is also extremely useful to
produce the effects of transverse loadings on thin walled members, such as angle sections, and hence
identifies the shear center or point of flexure in un-symmetric beam sections.
Background
The shear center locator is defined as the point in the plane of the cross-section through which the resultant
of transverse shearing stresses due to twisting (not torsion) will pass for any orientation of transverse load.
One of the assumptions made in the development of theory of pure bending is that loaded member is
symmetric with respect to the plane of couple and the loads are always applied in the plane of symmetry.
However, when this assumption is not satisfied i.e for un-symmetric cross-sections and un-symmetric
loading conditions, the beam will twist in longitudinal axis. Thus, in order to avoid twisting, the load has to
be applied in such a plane where the line of action of load passes through "shear center* also known as
center of flexure or center of twist.
1. For bi-axial symmetric cross-sectional members, the shear center coincides with the centroid of the
cross-sectional area.
2. For uni-axial symmetric cross-section members, the shear center is always located on the axis of
3. If uni-axial symmetric beams positioned such that the plane of symmetry is the neutral axis (i.e
passing through C.G) and the plane of load is perpendicular to the neutral axis, then load line cannot
pass through the C.G and shear center simultaneously. For such cases bending force may cause the
twisting of beam even if the load passes through the centroid. Shear center locator identifies the
plane of bending passing through the shear center, so that twisting can be avoided on application of
load on this plane.
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Objective
1. The aim of developing this product is to develop a simple and economical setup for determining the
shear center.
2. To produce a setup such that under the application of load, over an un-symmetric thin beam section,
it produces the ideal loading conditions i.e locate planes suitable to place load and avoid twisting
along with bending.
Detail Specifications
1. The shear center locator has a channel section (1), (length=550mm, breadth= 130mm, height=60mm
and thickness=5mm) to serve as a base.
2. Two angle sections (2) of size 130x 65x 80mm and thickness 5mm placed adjacent to each other to
form a channel.
3. A pipe of dimensions length=165mm, internal diameter= 65mm . outer diameter= 68mm having a
slot of 5mm across the length .It is used as a fixing frame on angle section with slot on the upper
side.
4. Three pieces of pipe section, length= 155mm, outer diameter= 65mm, inner diamcter^62min MS
beam holders.
5. Four plates of size , length= 25mm, breadth= 25mm, thickness- 5mm with a hole of diameter=8mm
at the center of each plates and fixed on the fixing frame adjacent to each other with 10mm distance
between them.
6. Beam samples of size length =650mm, breadth^ 100mm, 88mm, and 60mm of galvanized sheet that
are formed into unsymmetrical channels and unequal angle sections. These are then casted in beam
holder and beam socket with battery compound.
7. Rings of Perspex pipe with dimensions, diameter 75mm , thickness 3mm and length -20mm are used
to serve as sockets.
8. Additional ring of inner diameter =75mm, outer diameter = 80mm, thickness= 3mm is bounded to
the socket to serve as support for the loading frame.
9. A loading frame of Perspex sheet with dimensions, length= 90mm, breadth- 90mm and thickness=
20mm. It has central hole of diameter =75mm with a slot at the top for moving the slot transversely
and to fix a scale and lead screws. The lower corners of the frame are cut at 45° along with a
threaded hole of 8mm for clamping the loading frame to the end socket.
10. The dial gauges to measure the deflection in the beam of unsymmetrical section.

Claims:
1. A shear center locator, where a channel section base (1) is used to mount a support (2) along with a
fixing frame (3) having clamps(4) for holding the beam sections in a beam holder(5). which have a
beam socket(6) at the other end of the beam and a loading frame (7) for hanging weights and plotting
sheet, said frame also has load shifting and deflection measuring system (8) along with a load bead
(9) at its top to hang the load.
2. A shear center locator as claimed in claim 1 , wherein the base (1) has a definite U shaped channel
section.
3. A shear center locator as claimed in claim 2 , wherein the U shaped channel section (1) mounted
with a support(3) of definite L shaped section.
4. A shear center locator as claimed in claim 1 to 3 . wherein fixing frame (3) has a cylindrical shape
with cut section along its whole length and having clamps(4) for gripping the beams .
5. A shear center locator as claimed in claim 1 to 4 , where in a beam socket (6) is provided to hold the
beams at other ends and is circular in section of definite dimensions.
6. A shear center locator as claim in claim 5, where in the loading frame (7) supports the mechanism
for plotting shear center.
7. A shear center locator as claimed in claim 5 , 6. where in load shifting mechanism sysiem (8) is
provided to support dial gauge for measuring deflection at its two ends .
8. A shear center locator as claimed in claim 7 , where in a load bead (9) is provide to hand and adjust
the load position to obtain the actual location of intersection points of two different loads lines.