Slutter, Roger G

English

Lehigh University: Lehigh Preserve

Lehigh University
Lehigh Preserve
Fritz Laboratory Reports Civil and Environmental Engineering
1984
History of five million pound testing machine, July
1984
Roger G. Slutter
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Recommended Citation
Slutter, Roger G., "History of five million pound testing machine, July 1984" (1984). Fritz Laboratory Reports. Paper 1628.
http://preserve.lehigh.edu/engr-civil-environmental-fritz-lab-reports/1628
237 Jt&A
July 1981
July 1984
FRITZ ENGINEERING LABORATORY
LEHIGH UNIVERSITY
Bethlehem, PA.
FIVE MILLION POUND TE~TING MACHINE HISTORY
Run ENGINEERING
i':~ABORATORY UBRARY
A brief history of the calibration of our five million pound
testing machine follows. When the machine was. new it was calibrated
to the full capacity of 5,000,000 lbs. This calibration was done by
using a cluster of 300,000 lb. capacity proving rings. The results
of this calibration done in 1957 is given on Drawings 237-103, a copy
of which is attached. This procedure was the best approach available
at ·the time. However, the necessity of reading so many proving rings
simultaneously led to the conclusion that the accuracy of the testing
machine was better than the accuracy of the calibration procedure.
Since 1971 the calibration of the two high ranges of the testing
machine (2,000,000 and 5,000,000 lbs.) has been done annually using a
1,000,000 lb. load cell that has been previously calibrated at the
National Bureau of Standards. Verification. of the machine for loads
above 1,000,000 lbs. is done whenever we calibrate load cells. Cali-
bration traceable to the National Bureau of Standards for loads above
1,000,000 lbs. must be done using more than one load cell. This pro-
cedure is probibitive and the results are questionable.
We have a five million capacity strain gage load cell which is
used only to verify that the calibration that is performed up to a
load of one million pounds can be projected to the full capacity of
the machine. What we do with our own load cell is not traceable to
the National Bureau of Standards but it serves as a means of checking
our machine which satisfies us. We normally make a calibration run
with our own load cell following calibration of our machine by an
outside agent. This means to a load of 1,200,000 lbs. when four
proving rings are used or to 1,000,000 lbs. since a load cell of this
capacity traceable to the National Bureau of Standards has been avail-
able to us. On a few occasions we have loaded our load cell up to the
-1-

Five Million Pound Testing Machine History
full capacity of the machine. .An example of this is attached for the
date of 9/28/82. This is a verification rather than a calibration
because we consider our machine to be more accurate than our load cell.
Our machine is constructed with a single hydraulic capsule load
cell for six ranges of loading which are:
20,000 lbs.
50,000 lbs.
200,000 lbs.
500,000 lbs.
2,000,000 lbs.
5,000,000 lbs.
By the time that each of the six ranges has been calibrated up
to capacity, or to 1,000,000 lbs. in the case of the two high ranges,
we feel that the readings of the hydraulic capsule have been satis-
factorily checked out. An example of a full calibration of all. six
ranges is attached for the date 9/28/82. In December of 1976 we
calibrated ten load cells to 2,000,000 lbs. All of the calibration
curves were linear and identical but the calibration factor seemed to
be different than was expected. The calibration of our machine was
checked on l2/l6/76.by an outside agent. A copy of this calibration
is also attached. It was found that the ten load cells were wrong
and not our machine. We have been through many problems of this type
during the last 25 years and the problem has never been with the
testing machine. The latest calibration dated 9/29/83 is also at-
tached. The machine is calibrated annually in early October by an
outside agent using load cells calibrated by the National Bureau of
Standards.
When the testing machine is in use the load is read simultaneously
on two ranges of the machine. The photograph on the back of the
enclosed brochure shows that the control panel of the machine has two
readout dials. For instance whenever the 2,000,000 lb. range is in
use the load is also read on the 5,000,000 lb. range. Whenever these
two readings check and the hydraulic capsule has been checked by the
calibration of all six ranges, we are confident that the calibration
of the machine is well within the one percent accuracy required. In
-2-
Five Million Pound Testing Machine History
the calibration history of the machine the only range of the machine
that has ever been found to have an error greater than 'one percent is
the 20,000 lb. range. This problem came up last in 1964 when this
range was found to have an error of -1.22 percent at a load of 2,000
lbs.
We feel that the calibration.procedure for the machine is
adequate and that the reading of loads on two ranges of the machine
for loads above 1,000,000 lbs. is a sufficient check for loads above
the calibration level. It has been our experience in checking load
cells for the past 25 years that the error for loads above 1,000,000
lbs. is much less than one percent and the percentage error decreases
for higher loads. Any work which requires better calibration data
than we have on our machine can only be done at the National Bureau
of Standards.
Attachments: Drawings 237-103 (2)
Calibration of Load Cell (9/28/82)
Calibration of Load Cell (9/28/83)
Calibration of Load Cell (12/16/76)
by
Roger G. Slutter
-3-
Range
2.000.0001 B.
-
---r:--- 0
, 0 0 0"''___ 0 0 0
o 0 0' 0 0 0 0 0 __ 0 0
0_0 _ 0 - 0 - 0._ q. - q-q.- 0..::::::::- 0----------;
o q 0. q. 0 0 000 0o 0 0 00 0 0 0 g 0
o 0 0 0 0 (\J.. /~ to.. ... N(\J V (0 co ..: _ _ _ _
0~
0
0g
1
0
0
0
-0
..
0
.,
a
.;°L--J---4--~-+--+-+--+--+--f::::::::=~r-------1'0
Q 112% I---l.---~
0+ . ~I--- ' l/
o
o I---~ .~~ .10-'0 Dial Cop. ~~
, 200,000 LB.
Rangeo~
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o .--l..----
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It)
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01.-__°0~8- 8- 8 - 00 - 00 - 8-8- g:=::::::.. O..------------iO ° .. .. .. .. .. 00.. 0.. 0.. • ' ° ° 0 0 0 0
o 0 0 ~ 0 (\J ~ (0 ,CD (\J(\J ~ (0 ...., _ _ - - -
o
o
+
gL-~-4--1_-_+_.:...-_+--l_-+-_+-___1==:;::::::==+----:-----~
~ ~I-------
----
.20%Dial Cap• .--L----~
20,000 LB.
Range.
Support Gauging • .042
oTemp. =70 F.
o
o
-
•
--r----r---.-'
---r----Io-.r-__-.L
r::--- '__ 0o 0 _ 0 .:....- ~_ 0 _ 0 -=- 0 ~_~
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N 0 ,0 0 0 o. q. q q, q 0,
I 0 0 0 0 0 N V ,(0 co (\Jo N V (0 co _ _ _ _ _
+~eans Proving Ring More Than Dial Reading CALIBRATION CURVES
-Means Proving Ring Less Than Dial Reading, 5,000,000LB. TESTING MACHINE "
LEHIGH UNIVERSITY BETHLEHEM .PA.
237 - t03
"'237.18
'"'r--,--...,----r--.---r---r---.,..---,----.,.--...,...----------
g L----l---'""
~t---t--+---t-::.----ir---t--+--+L--'--::=----F=:::::::....-.J---1------------I
0 2 ~L----0+ ____
~ t--:.I'::'O-=O/c"7o "'"':D:-:j"'"":al:-c::"of-!::----.--tL-----::::::::==oof"":::::....--t----'1r---+--+--.J---1---------___1
+ .,J.r---~ ~
o K==+===t==::::t:::::==-r~~4~-"---::.:-~--ir---1..,~·".-"..-...-t--lr---_~5~0~0~0~..0~0~0~L..gB~.
.~ Range
g ----~
q. ----~o 0 0 1;---0 0 0 0 o·
o 0 goo 0 6-- 0 0 0 0q~--1o - 0 - 0 - o~ - 0 _ q- o~':::::::::- "1___..- "1- 0. -1
o 066 0 600 006N ci 0 0 0 0 0 0 .0 0
log ~ ~ q ~ ~ ~ ~ 0
o 100 =- ~ N N .. . ttl" ttl . V V " L';
500 000 LB.
Range
o
o
o
2· ---r-:--
10 ~o . 0" "0 ". 0 0 __ 0 " 0ol---~o- 0 - 0 - 0 - 0-0- 0 ~ 0::::::::::::: g - 0 -----------1
N
1
0 g 0 o~ o~ o~" ~ o~ o~__ q,
q o· 0
0
• 0 000 000o 0 ~ o. o. ~ 0 ~ 0~ 0 ~ N N ttl· ttl ~ V ~
o L----
~r---i"---r--+-----jr----+~-+--tV---:::;:;;;o~::::::::=--+--~-----------I
~'" 1/2~L----0+ ~
o f- ----~ .10% 0101 CoP. ~
0r:::::o:=t=::::::+==t=t:::::::t"~"'=::::::~1" ,V-_"i~----:-I'~-r_-t--:-_----:5~0~0~0~O !dLB~.~
----
-- Range
+Meons Proving Ring More Than Dial Reading ", ...............~
-Means Proving Ring Less Thon Dial Rea~ing V'~.
o 3/~~ .
o ~t--:--t---t--+~..,..."---,"~~-~,-:::.=---+---1--~-t--.J-----------1
"0 f- .15% Dial Cop.
+
237 -103
CALIBRATION" CU"RVES _ "
5,000,000 LB. TESTING MACHINE
LEHIGH UNIVERSITY BETHLEHEM ,PAt
: -
o
o
Ooo
ll')o
o ...............
T ~
o "Support Gouging =.042 ~ ...
o .- +---~oo=---4---I---'"
NO" .............. 1'-..I Temp. I: 7 0 F. . 1-""""""
o 0 0 0 0 0 .......... 0 0 0
o 0 0 0 0 ~o 0 0g o~ o. o. 0 O. 0 ................ 0.. O.~ 0 "''') 6 If) 0 If)__ 0S? ~ C\J C\J tt) ,.., q- q- --..... 10











History of five million pound testing machine, July 1984

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