This paper presents a computer-aided design (CAD) module able to analyze different manufacturing configurations of tubes used in mechanical assemblies, such as exhaust system manifolds. It can be included in the knowledge-based expert system category and has been implemented into a CAD platform as a dedicated module able to take into account manufacturing requirements related to tube bending, hydroforming, and cutting. The expert’s knowledge, in terms of set of rules and criteria, has been implemented by means of the automation tools of CATIAV5R10 according to the so-called methodological formal approach. The resulting module is able to join different tubes starting from their geometrical models, obtaining a set of manufacturing alternatives. Each of them is verified with respect to collisions with a bending machine and also in terms of hydroforming process feasibility. Only those solutions that satisfy these checks are accepted as feasible and ranked according to three evaluation criteria related to manufacturing cost and easiness. The system is completely automatic and able to analyze more than 100 different configurations in $<10min$. The feasible solutions are saved as CAD model to allow FEA of hydroforming and other possible CAE activities. Unfeasible solutions are deleted but reported and documented in a log file. The feasible solution rank is given in a table and has been developed according to a multicriteria approach to make optimal solution detection easier. The proposed test case aims to show and discuss these capabilities. By this module, two or more components of the exhaust system manifold can be manufactured in one stroke as a single component, starting from the same pipe and next trimmed to obtain the desired final parts. This capability can be used to reduce scraps and improve cycle time of the manufacturing process.

1.
Penoyer
,
J. A.
,
Burnett
,
G.
,
Fawcett
,
D. J.
, and
Liou
,
S. Y.
, 2000, “
Knowledge Based Product Life Cycle Systems: Principles of Integration of KBE and C3P
,”
Comput.-Aided Des.
0010-4485,
32
, pp.
311
320
.
2.
Plant
,
R.
, and
Gamble
,
R.
, 2003, “
Methodologies for the Development of Knowledge-Based Systems, 1982–2002
,”
Knowl. Eng. Rev.
0269-8889,
18
(
1
), pp.
47
81
. Cambridge University Press, Cambridge, UK.
3.
Buchanan
,
B. G.
,
Barstow
,
D.
,
Bechtal
,
R.
,
Bennett
,
J.
,
Clancy
,
C.
,
Kulikowski
,
C.
, and
Mitchell
,
T.
, “
Constructing an Expert System
,”
Building Expert Systems
,
F.
Hayes-Roth
,
D. A.
Waterman
, and
D. G.
Lenart
, eds.,
4.
Yen
,
J.
, and
Lee
,
J.
, 1993, “
A Task-Based Methodology for Specifying Expert Systems
,”
IEEE Expert
0885-9000,
8
(
1
), pp.
8
15
.
5.
Wielinga
,
B. J.
, et al.
, 1993, “
Towards a Unification of Knowledge Modeling Approaches
,”
Second Generation Expert Systems
,
J. M.
David
,
J. P.
Krivine
, and
R.
Simmons
, eds.,
Springer-Verlag
, Berlin.
6.
Koç
,
M.
, and
Altan
,
T.
, 2001, “
An Overall Review of the Tube Hydroforming (THF) Technology
,”
J. Mater. Process. Technol.
0924-0136,
108
(
3
), pp.
384
393
.
7.
Ahmetoglu
,
M.
,
Setter
,
K.
,
Li
,
X. J.
, and
Altan
,
T.
, 2000, “
Tube Hydroforming: Current Research, Applications and Need for Training
,”
J. Mater. Process. Technol.
0924-0136,
98
, pp.
224
231
.
8.
Koski
,
J.
, 1985, “
Defectiveness of Weighting Method in Multicriterion Optimization of Structures
,”
Commun. Appl. Numer. Methods
0748-8025,
1
, pp.
333
337
.
9.
Koski
,
J.
, and
Silvennoimen
,
R.
, 1987, “
Norm Methods and Partial Weighting in Multicriterion Optimization of Structures
,”
Int. J. Numer. Methods Eng.
0029-5981,
24
, pp.
1101
1121
.
10.
Tabucanon
,
M.
, 1981,
MultiCriteria in Industry Optimization
,
McGraw-Hill
, New York.