Press-Forming Butt-Jointed Plates With Deformed Sections
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Press-forming methods using butt-jointed plates face issues with stress concentration and cracking in joined portions during stretch-flange formation, leading to material deterioration and increased costs due to burring and hardening of welded areas.
Innovation Solution
A press-forming method and machine that incorporate deformed-shape sections near joined portions to guide peripheral length stretching and a restraining mechanism to minimize stress concentration, along with a forming mechanism that includes concave portions to prevent weld bead abutment and cockling, thereby reducing the occurrence of cracks and breakings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If plates are joined by welding to form a blank with different thicknesses, then the number of component parts is reduced and weight is decreased, but the joined portion becomes hardened and prone to cracking during press-forming
Solution Approach 1:
Deformed-shape sections are formed in advance in the vicinity of the joined portion before press-forming. These pre-formed sections are designed to deform in a direction that stretches the peripheral length, which prevents stress concentration during subsequent stretch-flange formation and eliminates the need for post-welding stress relief operations
Solution Approach 2:
The blank is designed with different plate thicknesses in different areas to optimize local properties. The joined portion is specifically treated with deformed-shape sections that have different geometric characteristics from other areas, creating local quality variations that protect the welded joint while maintaining overall structural integrity
2Shape
If stretch-flange formation is performed on a blank with joined portions, then the desired shape is achieved, but stress concentration occurs in the joined portion causing cracks and breakings
Solution Approach 1:
The deformed-shape sections are formed beforehand in the blank, creating a predetermined deformation pattern that guides the stress distribution during stretch-flange formation. This preliminary shaping ensures that when the stretch-flange formation occurs, the stress is evenly distributed and does not concentrate at the joined portion, thereby preventing cracks while achieving the desired final shape
Solution Approach 2:
The deformed-shape sections act as an intermediary element between the joined portion and the stretching region. These sections are designed to deform in a specific direction that protects the joined portion from direct stress concentration, serving as a buffer zone that mediates the stress transfer during press-forming
Data Source
AI summary
In a press-forming method, a plurality of plates are prepared and end faces of the plurality of plates are butt joined to obtain a blank having joined portions. The blank has deformed-shape sections formed in a vicinity of the joined portion so as to deform in a direction along which peripheral lengths of the deformed-shape sections are stretched. Press-forming, involving stretch-flange formation, is carried out on the blank so as to allow the joined portions to be included in stretching regions, respectively. Also, the stretch-flange formation is carried out on the blank while restraining ends of the joined portion of the blank.