Energy directors (EDs) have been widely used in ultrasonic welding (UW) of polymers and polymer-based composites. They help concentrate the welding energy and localize the weld at the location where the EDs are present. However, the utilization of EDs increases manufacturing cost and time, especially for complex parts and structures. This paper presents a method for UW of carbon fiber reinforced composite without using EDs. A reusable annular clamp (called a blankholder) is used as part of the weld tool to apply a variable force (called blank holding force) on the composite sheets during the UW. The effect of the blank holding force (BHF) on the weld formation is investigated. The results show that the duration of the BHF had significant impact on the weld formation. There is a critical duration with which a localized weld can form. Suitable durations of BHF at different levels of welding energy are determined by experiments. The main function of the BHF is to create an initial melting area by improving the contact condition. The initial melting area will act as an ED to concentrate the welding energy, and therefore, promotes the formation of a localized weld.

References

References
1.
Zhi
,
Q.
,
Tan
,
X. R.
,
Lu
,
L.
,
Chen
,
L. Y.
,
Li
,
J. C.
, and
Liu
,
Z. X.
,
2017
, “
Decomposition of Ultrasonically Welded Carbon Fiber/Polyamide 66 and Its Effect on Weld Quality
,”
Weld. World
,
61
(
5
), pp.
1017
1028
.
2.
Da Costa
,
A. P.
,
Botelho
,
E. C.
,
Costa
,
M. L.
,
Narita
,
N. E.
, and
Tarpani
,
J. R.
,
2012
, “
A Review of Welding Technologies for Thermoplastic Composites in Aerospace Applications
,”
J. Aerosp. Technol. Manage.
,
4
(
3
), pp.
255
265
.
3.
Yousefpour
,
A.
,
Hojjati
,
M.
, and
Immarigeon
,
J. P.
,
2004
, “
Fusion Bonding/Welding of Thermoplastic Composites
,”
J. Thermoplast. Compos. Mater.
,
17
(
4
), pp.
303
341
.
4.
Tolunay
,
M. N.
,
Dawson
,
P. R.
, and
Wang
,
K. K.
,
1983
, “
Heating and Bonding Mechanisms in Ultrasonic Welding of Thermoplastics
,”
Polym. Eng. Sci.
,
23
(
13
), pp.
726
733
.
5.
Villegas
,
I. F.
, and
Bersee
,
H. E. N.
,
2010
, “
Ultrasonic Welding of Advanced Thermoplastic Composites: An Investigation on Energy-Directing Surfaces
,”
Adv. Polym. Technol.
,
29
(
2
), pp.
112
121
.
6.
Palardy
,
G.
, and
Villegas
,
I. F.
,
2017
, “
On the Effect of Flat Energy Directors Thickness on Heat Generation During Ultrasonic Welding of Thermoplastic Composites
,”
Compos. Interfaces
,
24
(
2
), pp.
203
214
.
7.
Benatar
,
A.
,
1989
, “
Ultrasonic Welding of PEEK Graphite APC-2 Composites
,”
Polym. Eng., Sci.
,
29
(
23
), pp.
1705
1721
.
8.
Chuah
,
Y. K.
,
Chien
,
L. H.
,
Chang
,
B. C.
, and
Liu
,
S. J.
,
2000
, “
Effects of the Shape of the Energy Director on Far-Field Ultrasonic Welding of Thermoplastics
,”
Polym. Eng. Sci.
,
40
(
1
), pp.
157
167
.
9.
Liu
,
S. J.
,
Chang
,
I. T.
, and
Hung
,
S. W.
,
2001
, “
Factors Affecting the Joint Strength of Ultrasonically Welded Polypropylene Composites
,”
Polym. Compos.
,
22
(
1
), pp.
132
141
.
10.
Lu
,
L.
,
Zhi
,
Q.
,
Gao
,
Y. H.
,
Liu
,
Z. X.
, and
Wang
,
P. C.
,
2017
, “
Repairing Ultrasonic Welded Carbon Fiber-Reinforced Nylon 66 Composite
,”
Weld. J.
,
96
(
12
), pp.
439s
450s
.https://s3.amazonaws.com/WJ-www.aws.org/supplement/WJ_2017_12_s439.pdf
11.
Villegas
,
I. F.
,
2014
, “
Strength Development Versus Process Data in Ultrasonic Welding of Thermoplastic Composites With Flat Energy Directors and Its Application to the Definition of Optimum Processing Parameters
,”
Compos. Part A
,
65
, pp.
27
37
.
12.
Luo
,
Y.
,
Zhang
,
Z. B.
,
Wang
,
X. D.
, and
Zheng
,
Y. S.
,
2010
, “
Ultrasonic Bonding for Thermoplastic Microfluidic Devices Without Energy Director
,”
Microelectron. Eng.
,
87
(
11
), pp.
2429
2436
.
13.
Levy
,
A.
,
Le Corre
,
S.
, and
Villegas
,
I. F.
,
2014
, “
Modeling of the Heating Phenomena in Ultrasonic Welding of Thermoplastic Composites With Flat Energy Directors
,”
J. Mater. Process. Technol.
,
214
(
7
), pp.
1361
1371
.
14.
Villegas
,
I. F.
, and
Palardy
,
G.
,
2017
, “
Ultrasonic Welding of CF/PPS Composites With Integrated Triangular Energy Directors: Melting, Flow and Weld Strength Development
,”
Compos. Interfaces
,
24
(
5
), pp.
515
528
.
15.
Wang
,
K. F.
,
Li
,
Y.
,
Banu
,
M.
,
Li
,
J. J.
,
Guo
,
W. H.
, and
Khan
,
H.
,
2017
, “
Effect of Interfacial Preheating on Welded Joints During Ultrasonic Composite Welding
,”
J. Mater. Process. Technol.
,
246
, pp.
116
122
.
16.
Chen
,
L. Y.
,
Zhi
,
Q.
,
Li
,
J. C.
,
Liu
,
Z. X.
, and
Wang
,
P. C.
,
2018
, “
Single-Sided Ultrasonic Welding of CF/Nylon 6 Composite Without Energy Directors
,”
Weld. J.
,
97
(
1
), pp.
17s
25s
.https://s3.amazonaws.com/WJ-www.aws.org/supplement/2018.97.002.pdf
17.
Gao
,
Y. H.
,
Zhi
,
Q.
,
Lu
,
L.
,
Liu
,
Z. X.
, and
Wang
,
P. C.
,
2018
, “
Ultrasonic Welding of Carbon Fiber Reinforced Nylon 66 Composite Without Energy Director
,”
ASME J. Manuf. Sci. Eng.
,
140
(
5
), p.
051009
.
18.
Emblom
,
W. J.
,
2017
, “
Indirect Strain Control in Aluminum Stamp Formed Pans
,”
ASME J. Manuf. Sci. Eng.
,
139
(
8
), p.
081013
.
19.
Zhang
,
W. F.
, and
Shivpuri
,
R.
,
2008
, “
Investigating Reliability of Variable Blankholder Force Control in Sheet Drawing Under Process Uncertainties
,”
ASME J. Manuf. Sci. Eng.
,
130
(
4
), p.
041001
.
20.
Kaya
,
S.
,
2011
, “
Using Servo-Drive Presses to Determine the Effect of Blankholder Pressure on Temperature Change in Warm Forming of Sheet
,”
ASME J. Manuf. Sci. Eng.
,
133
(
6
), p.
061024
.
21.
Wang
,
K. F.
,
Shriver
,
D.
,
Li
,
Y.
,
Banu
,
M.
,
Hu
,
S. J.
,
Xiao
,
G. X.
,
Arinez
,
J.
, and
Fan
,
H. T.
,
2017
, “
Characterization of Weld Attributes in Ultrasonic Welding of Short Carbon Fiber Reinforced Thermoplastic Composites
,”
J. Manuf. Process.
,
29
, pp.
124
132
.
22.
Villegas
,
I. F.
,
2015
, “
In Situ Monitoring of Ultrasonic Welding of Thermoplastic Composites Through Power and Displacement Data
,”
J. Thermo. Compos. Mater.
,
28
(
1
), pp.
66
85
.
23.
Zhi
,
Q.
,
Gao
,
Y. H.
,
Lu
,
L.
,
Liu
,
Z. X.
, and
Wang
,
P. C.
,
2018
, “
Online Inspection of Weld Quality in Ultrasonic Welding of Carbon Fiber/Polyamide 66 Without Energy Directors
,”
Weld. J.
,
97
(
3
), pp.
65s
74s
.https://s3.amazonaws.com/WJ-www.aws.org/supplement/2018.97.006.pdf
24.
Wang
,
K.
,
Shriver
,
D.
,
Banu
,
M.
,
Hu
,
S. J.
,
Xiao
,
G.
,
Arinez
,
J.
, and
Fan
,
H. T.
,
2017
, “
Performance Prediction for Ultrasonic Spot Welds of Short Carbon Fiber-Reinforced Composites Under Shear Loading
,”
ASME J. Manuf. Sci. Eng.
,
139
(
11
), p.
111001
.
25.
Meyers
,
M. A.
, and
Chawla
,
K. K.
,
2008
,
Mechanical Behavior of Materials
,
2nd ed.
,
Cambridge University Press
,
Cambridge, UK
.
26.
Meirovitch
,
L.
,
1967
,
Analytical Methods in Vibrations
,
Macmillan Publishing Co
,
New York
.
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