Study on alignment test based on ASTM E1012 and Chinese guideline

ACTA IMEKO | www.imeko.org December 2020 | Volume 9 | Number 5 | 159

ACTA IMEKO
ISSN: 2221-870X
December 2020, Volume 9, Number 5, 159 - 162

STUDY ON ALIGNMENT TEST BASED ON ASTM E1012 AND CHINESE

GUIDELINE

Xiaobing Zhao1, Wansheng Li2, Minghui Fei3, Xiaolan Zheng4, William Huang5

1 Wuxi Institute of Metrology and Testing, Wuxi, China, zxb@wxmtc.com

2 Shandong Institute of Metrology, Jinan, China, liwansheng@sdim.cn
3 Wuxi Institute of Metrology and Testing, Wuxi, China, fmh@wxmtc.com

4 Yunnan Institute of Measuring and Testing Technology, Kunming, China, zhengxlan06@163.com
5 GTM China Office, Shanghai, China, william.huang@gtmchina.cn

Abstract

This paper describes the study about alignment

test on testing machine. It is based on the standards

of ASTM E1012-14 (Standard Practice for

Verification of Testing Frame and Specimen

Alignment Under Tensile and Compressive Axial

Force Application) and Chinese calibration

guideline. The strain-gauge specimens of ASTM

and reference extensometer of Chinese guideline

were both tested on one testing machine. The test

results were analyzed and compared. The

traceability about both methods were also discussed.

Meanwhile the amplifier was calibrated before test.
It is the first time in China to performance this

comparison test.

Keywords: alignment test, ASTM E1012,

Chinese alignment guideline

1. INTRODUCTION

The alignment on testing machine is very

important to obtain the right test results of material.

The standard of ASTM E1012-14 [1] and Chinese

guideline [2] [3] both descript how to test the

alignment. But the methods are different, and the

philosophy of traceability are also not same. To

prove both methods reliable on testing the

alignment at one testing machine, it is necessary to

do a comparison test to see if there will be big

tolerance by these two standards. Therefore, two

laboratories in China, both own both equipment of

ASTM E1012 and Chinese alignment guideline,

decide to do the comparison test in 2019.

ISO 23788:2012 (Metallic materials – Verifi-

cation of the alignment of fatigue testing machines)

[4] also describes about alignment test, but it is very

similar as ASTM E1012. The most difference

between ISO 23788 and ASTM E1012 is: there are

total 12 pieces of strain-gauges on three levers at the

transducer according to ASTM, but there are only 8

strain-gauges on two levers according to ISO.

The details and difference between ASTM

E1012 and Chinese guideline are: the specimen, the

procedure, the calculation, the classification

(deviation) and the traceability. They are described

in section 2 to section 5.

2. THE EQUIPMENTS

According to ASTM E1012, there are four

strain-gauges at same lever but different position on

alignment specimen (so-call alignment transducer).

Total 12 or 8 pieces of strain-gauges on 3 or 2 levers

at the transducer. As Figure 1:

Figure 1: Strain-gauge transducer

The equipment to be performance alignment test

consist: an alignment specimen with 12 pieces of

strain-gauges, amplifier of 12 channels, the software.

They are called alignment tool kit by the product

from ZwickRoell, a Germany testing machine

manufacturer. As Figure 2.

The alignment specimen details (sharp,

dimension) as Figure 3.

http://www.imeko.org/
mailto:zxb@wxmtc.com
mailto:liwansheng@sdim.cn
mailto:fmh@wxmtc.com
mailto:zhengxlan06@163.com
mailto:william.huang@gtmchina.cn

ACTA IMEKO | www.imeko.org December 2020 | Volume 9 | Number 5 | 160

Figure 2: Alignment tool kit from ZwickRoell

Figure 3: Alignment specimen

The amplifier is type quantumX MX1615B.
Excitation voltage is 10V and full-bright are set in

the software. 12 channels of this amplifier are used

to be connected to the alignment specimen.

According to Chinese guideline JJG 475-2008:

verification of electric testing machine, and JJG

556-2011：verifications of uniaxial fatigue testing

machine [2] [3], the alignment kit is twins’

extensometers and specimens, as Figure 4.

Figure 4: twins’ extensometers on specimen

The twins’ extensometers mean there are two

extensometers: one is attached on the left side of

specimen and another is on the right side. The

extensometer is used for measuring the elongation

of the specimen during tensile test. Theoretically the

elongation of both sides of specimen should be same

if the alignment of the testing machine is perfect.

The specimen’s specification is descripted as in

Table 1 and Figure 5.

Fmax of testing
machine in kN

diam.d
in mm

gauge

length Lo

in mm

L in
mm

material

[100---600) 10 100 130
steel

No.45

(30---100) 10 100 130
alloy

steel

Table 1: the dimension of the specimen

Figure 5: the drawing of the specimen

3. PROCEDURE

We use a ZwickRoell testing machine Z050 to

do test. The capacity of the machine force is 50KN.

The classification of this testing machine is class 0.5.

3.1 According to ASTM E1012-14:

1. clamp the alignment transducer at the top grip,

zero the signal, clamp the lower grip.

Apply a small force to see all signal ok and then

remove the force.

2. increase the force and apply it to 4 %, 6 % and

8 % of the capacity of the testing machine, that

means 2 kN, 3 kN, and 4 kN. Record the

measurement value. And calculate all the data

automatic by software.

(The original is to apply the force to 10%, 20%

and 40% of the machine capacity, here we apply 4%,

6% and 8% of the machine capacity)

3. remove the force to zero. Change the position

of the alignment transducer from position 0° to 180°

and repeat the step 2.

4. remove the force to zero. Change the position

from 180° back to 0°, and repeat step 2.

3.2 According to Chinese guideline:

1. clamp the specimen on both grips of testing

machine

2. apply the force of 0.5 % of the machine and

attach the twin’s extensometers at the position of 1

and 3 on the specimen as Figure 6.

Apply the force to 1 % of the machine and zero

the signal of both extensometers. Apply to the force

to 10 % of the machine. That means the pre-apply.

Do it three times.

3. remove the force to zero. Apply the force to

1 % of the machine and zero the signal of both

extensometers. Increase the force to 4 %, 6 % and

8 % of the machine. Record all the data.

(The original is to increase the force to 4% , 6%,

8% and 10% of the machine capacity, here we

apply 4%, 6% and 8% of the machine capacity)

http://www.imeko.org/

ACTA IMEKO | www.imeko.org December 2020 | Volume 9 | Number 5 | 161

4. change the extensometers to positions 2 and

position 4. Same procedure as step 2 and 3.

Figure 6: the positions for twins’ extensometers attached

4. DATA ANALYSISI

According to ASTM E1012, the Cylindrical

strain-gauged alignment specimen use following

equations:(As Figure 7）

Figure 7: the equations of PB

PB is the percent bending, which is the value of

the alignment.

From the test 3.1, all data were collected. Here

we show the data from the middle lever of the strain-

gauge, as in Table 2.

In ASTM E1012, the original “record data points

at 10%, 20% and 40% of the force transducer range

or testing machine capacity”, but here we only apply

the force to 4%, 6% and 8%, and the best value of

PB is 10.7 at 4kN (8% of the machine capacity of

50K), because we try to make the same force apply

as Chinese calibration guideline.

Force Position PB (%)
PB

（Ave）

2 kN middle

0° 25.3

21.5 180° 16.89

0° 22.3

3 kN middle

0° 17.42

14.3 180° 11.62

0° 13.94

4 kN middle

0° 14.08

10.7 180° 8.98

0° 9.12

Table 2: the data of the middle lever of the strain-

gauge

According to the Chinese guideline, the value of

e is the alignment specification of the testing

machine. It uses following equations: (As Figure 8）

Figure 8: the equations of e

From the test 3.2, we collect the data of e as in

Table 3.

Force e (%)

2 kN 10.3

3 kN 7.3

4 kN 5.4

Table 3: the data by test 3.2

Test results of test 3.1 and test 3.2 are compared

as in Table 4.

Force PB (%) e (%)

4 % of

machine
2 kN 21.5 10.3

6 % of

machine
3 kN 14.3 7.3

8 % of

machine
4 kN 10.7 5.4

Table 4: the results compared

http://www.imeko.org/

ACTA IMEKO | www.imeko.org December 2020 | Volume 9 | Number 5 | 162

The PB results are almost exactly double the e

results. But it should be no coincidence because the

classification is different as discussion later.

5. DISCUSSION

The classification of alignment by ASTM E1012:

and Chinese calibration guideline is different, as in

Table 5.

ASTM E1012

Classification

(%)

Classification

of testing

machine

(%)

5 5

0.5 12

8 8 1 15

10 10 2 20

Table 5: the different classification.

The standard of ASTM only talks about the

alignment classification, instead of the machine.

The Chinese guideline takes care the machine must

fulfil the requirement of the alignment.

The data from test 3.1 does not apply enough

force on the strain-gauge specimen according to

ASTM E1012. Therefore, it cannot give decision

that PB of 10.7 does not fulfil class 10.

The data from 3.2 test shows that the machine

full fill class 0.5, because the alignment of e is

10.3%, which is within the tolerance of 12%.

Additional topic need taken care is the

traceability. In ASTM E1012, there mentioned:

“8.1.1 Calibration of strain-gaged alignment

transducers is not required by this standard.

Traceable national standards do not generally exist

for such calibrations. However, great care should be

taken in the manufacture of strain-gage alignment

transducers used for the determination of alignment”

That means only the amplifier can be calibrated.

We did calibration as in Figure 9 for this. The

standard signal is created by a device.

The deviation between standard signal and

amplifier (mV/V) is less than -0.3%. Its fine. The

details data as shown in Table 6.

standard
amplifier

mV/V

amplifier

μm/m
deviation %

0 0.0003 0.4 -

0.25 0.2499 254.6 -0.04

0.5 0.4997 509 -0.06

0.75 0.7485 763 -0.20

1 0.9977 1017 -0.23

Table 6: calibration data of amplifier.

Figure 9: The standard signal (above), and the amplifier

to be calibrated (below)

Concerning the calibration on twins’

extensometers of Chinese, its easy: calibrate the two

extensometers one by one. Each is done by a master

extensometer. They can be traceability to the

primary standard of length. That mean all the

Chinese alignment kit can be calibrated.

6. SUMMARY

The main difference between the standard of

ASTM E1012-14 and Chinese calibration guideline

about alignment are classification, tool kit hardware,

and the force apply.

ASTM is more accuracy on alignment

specificity of testing machine. But there is no

solution for the whole traceability.

The method of Chinese guideline is easier to

handle and can be traceability.

Both methods are reliable to determine the

alignment of the material testing machine.

7. REFERENCES

[1] ASTM E1012-14. Standard Practice for
Verification of Testing Frame and Specimen

Alignment Under Tensile and Compressive Axial

Force Application.

[2] JJG 475-2008: verification of electric testing
machine,

[3] JJG 556-2011. verifications of uniaxial fatigue
testing machine.

[4] ISO 23788:2012 (Metallic materials – Verification
of the alignment of fatigue testing machines)

http://www.imeko.org/