®
L a r g e S t r u c t u r e s S e t
O p e r a t i o n
8
Operation
Assembling Beams
All beams attach to connectors in the same way. Use the included screws (6-32, slotted) to attach beams to a con-
nector (such as the half round connector) as illustrated.
Adding Load Cells
To measure the compression and tension forces in indi-
vidual members of a structure, add load cells (available
separately) to the PASCO Structure. Replace a beam
with two shorter beams and a load cell.
#5 beam = load cell + two #3 beams
#4 beam = load cell + two #2 beams
#3 beam = load cell + two #1 beams
Use thumbscrews to attach two beams to a load cell as
shown in the figure.
When using load cells, assemble your structure with the screws loose. This will simplify the analysis by ensuring
that the members experience only tension and compression without moments.
Example: Bridge with Load Cells
Static Load
The bridge shown in the figure incorporates six load
cells to measure the tension or compression in vari-
ous members. A hanging mass is used to apply load.
The mass is adjusted so that the compression in one
of the legs is 1.0 N. Compression is registered as a
positive value and tension as a negative value.
If the screws are loose, then the theoretical analysis
of the bridge can be carried out by assuming that the net force at each node is zero. Thus, the vertical component
of compression in the left-most diagonal member must be 1 N (to oppose the force applied by the leg). The hori-
zontal component must also be 1 N since the member is at a 45° angle. The predicted resultant force is:
Attaching beams to connectors
A load cell combined with two #2 beams is the same
length as a #4 beam
Load Cell
#2
#2
#4
Bridge with Load Cells
1.0 N
(
)
2
1.0 N
(
)
2
+
1.4 N
=