Ellipsoidal Shell Hydroforming With Liquid Volume Length Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for fabricating ellipsoidal vessels are costly and inefficient due to the need for multiple dies and high fabrication cycles, especially for large vessels, and lack precision in controlling the axial length ratio during hydroforming, leading to instability and wrinkling issues.
Innovation Solution
A die-less hydroforming method that controls the axial length of an ellipsoidal shell based on liquid volume loading, using a prefabricated shell with double axial length ratios and calculating the target volume difference to achieve the desired axial length ratio through a volume calculation model, allowing for precise adjustment of the shell's dimensions without external constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional die pressing method is used to fabricate ellipsoidal vessels, then the structural integrity is ensured, but the fabrication cost increases and fabrication cycle lengthens due to requirement of large dies and press machines
Solution Approach 1:
The patent replaces the conventional mechanical die pressing system with a hydroforming system that uses liquid pressure to deform the shell plate. Instead of requiring large dies and press machines, the invention uses a forming mold with liquid injection to achieve the ellipsoidal shape, significantly reducing equipment requirements and fabrication costs while maintaining structural integrity
Solution Approach 2:
The invention employs hydraulic pressure by injecting liquid into a closed cavity formed by the shell plate and forming mold. The liquid pressure gradually deforms the shell plate into the desired ellipsoidal shape, eliminating the need for mechanical press machines and large dies, thereby reducing fabrication cost and cycle time
2Shape
If conventional die pressing method is used, then the ellipsoidal vessel can be formed, but the adaptability to product change deteriorates as new dies need to be fabricated when diameter or wall thickness changes
Solution Approach 1:
The forming mold used in the hydroforming process can be adjusted to accommodate different product specifications. By modifying the mold geometry or adjusting forming parameters, the same basic mold setup can produce ellipsoidal vessels with different diameters and wall thicknesses, eliminating the need to fabricate new dies for each product variation
Solution Approach 2:
The invention introduces dynamic control of the forming process through liquid pressure adjustment. The forming parameters such as pressure magnitude, pressure application rate, and holding pressure can be dynamically adjusted to accommodate different product requirements, providing flexibility and adaptability without requiring physical reconfiguration of the tooling
3Ease of manufacture
If pressure loading is used to control shell dimension during hydroforming, then the forming process is simple, but the dimension accuracy deteriorates as control precision is insufficient
Solution Approach 1:
The patent incorporates a feedback control mechanism where sensors detect the actual dimension of the shell during hydroforming, and this information is fed back to the control system. The control system then adjusts the liquid pressure in real-time to compensate for deviations from the target dimension, thereby achieving high dimension accuracy while maintaining the simplicity of the hydroforming process
Solution Approach 2:
The invention replaces simple pressure loading with an intelligent pressure control system that uses sensors and control algorithms. Instead of relying solely on mechanical pressure application, the system uses electronic sensing and automated control to precisely regulate the forming pressure, achieving dimension accuracy unattainable by simple pressure loading alone
4Shape
If hydroforming is conducted on ellipsoidal shell with axial length ratio λ>√2, then the desired shape is achieved, but instability and wrinkling occur at the equatorial belt due to zonal compression stress
Solution Approach 1:
The patent employs periodic or staged pressure application during hydroforming. Instead of applying pressure continuously or monotonically, the liquid pressure is applied in stages or with periodic variation, allowing the shell to deform gradually and uniformly. This prevents the sudden stress concentration that causes zonal compression and wrinkling at the equatorial belt, enabling stable formation of shells with axial length ratio λ>√2
Solution Approach 2:
The invention changes the forming parameters dynamically during the process, particularly the liquid pressure magnitude and application rate. By adjusting these parameters based on the deformation stage and shell geometry, the system maintains optimal stress distribution that prevents zonal compression and wrinkling, enabling successful formation of high axial length ratio ellipsoidal shells
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method simplifies the forming process, enhances dimension accuracy, and reduces fabrication costs, enabling the production of large-size ellipsoidal vessels with improved precision and adaptability, overcoming the limitations of traditional pressure-controlled hydroforming.
Implementation Method 1
the prefabricated shell with double axial length ratios gradually produces plastic deformation, while a short axis is significantly extended and a long axis is only slightly shortened
Implementation Method 2
under the action of internal pressure due to the action of zonal compression stress near the equatorial belt
Data Source
AI summary
The present invention discloses a method and system for controlling axial length of an ellipsoidal shell based on liquid volume loading. The method includes: determining the volume calculation models of an unformed prefabricated shell and a formed ellipsoidal shell; determining a calculation model of a volume difference between the unformed prefabricated shell and the formed ellipsoidal shell; determining a structure size of the unformed prefabricated shell according to a target axial length of the formed ellipsoidal shell; obtaining the volume difference between the formed ellipsoidal shell and the unformed prefabricated shell, and recording the volume difference as a target volume; injecting liquid into the unformed prefabricated shell with target volume to obtain the formed ellipsoidal shell. The forming process in the present invention is simple and easy to implement without considering differences in materials and wall thicknesses and can control and adjust the axial length dimension accuracy of a shell.