Tube Hydroforming: System Analysis and Process Design

M. Strano, Tube HydroForming: System Analysis and Process Design 
11 
design. In order to shorten the development time and efforts for THF process, supplemental codes and 
techniques are being developed. Adaptive simulation technique, for instance, iterates between appropriate internal 
pressure and axial feeding inputs to ensure a part without any fracture and wrinkles. These techniques are still 
under development and Part II of the present dissertation is focused on them. 
1.2. The system approach 
A system approach is chosen in the present work for the analysis of THF technology. Indeed, both in research 
activities and in design and development of a new Tube HydroForming operation, attention must be paid to 
several aspects and issues of the technology and a system approach to the resolution of problems is highly 
recommended. In other words, when designing a new process, problems and improvements in each area of the 
THF technology and their interaction should be considered. The main components and key issues of a complete 
THF system can be listed as in Figure I- 2. 
For each and every one of the mentioned components of the THF system, several issues should be studied and 
considered for process analysis and design. However, the most critical points for each of the mentioned 
components, from an industrial point of view, are: 
A. determination of quality and material properties of incoming tubes (see Chapter I-2); 
B. design of preform shapes, optimization of pre- (bending, crushing) and post- forming (punching, trimming) 
operations (see Chapter I-3); 
C. determination of guidelines for rapid design of dies and tools (see Chapter I-4); 
D. models for evaluation and prediction of die-workpiece interface conditions (wear, friction and lubrication) 
(see Chapter I-5); 
E. numerical and analytical methods for analysis of deformation mechanics (see Chapter I-6); 
F. design of low cost equipment and press (see Chapter I-7); 
G. evaluation of performance of the hydroformed part (mechanical resistance, springback) (see Chapter I-8); 
The most recent industrial and research trends and activities for each of the listed points will be described in the 
following chapters. Most of the issues presented in Chapters from I-2 to I-4 derive from original ideas and 
research work, which are presented in an appropriate reference scientific framework. Chapter from I-5 to I-8 
result from a deep and prolonged bibliographic study, although the matter is presented with an emphasis on the 
activities carried out at the ERC/NSM and the approach is strongly influenced by the research strategy and 
approach used at the mentioned institute. 
 
 
A. incoming tubes; 
B. preforming and post-
forming systems and 
methods; 
C. dies and tools; 
D. die-workpiece interface; 
E. deformation Mechanics; 
F. equipment and press; 
G. hydroformed part . 
C
Tools /
Dies
A
Incoming
Tube
D
Tool-Workpiece
Interface
E
Deformation
Mechanics
F
Equipment /
Environment / Press
G
Hydroformed
part
B
Bending /
Preforming
 
Figure I- 2: The Tube HydroForming System