T-Shaped Weld Joint Structure for Lower Stress Concentration
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Solution Overview
Problem
T-shape welding joints often experience stress concentration due to small toe angles and non-welded root portions, leading to potential fractures in vehicle bodies.
Innovation Solution
The welding structure features a first base material with curved portions and a second base material with a bent portion, where the offset and curvature of these elements ensure a larger toe angle and stable molten metal introduction, reducing stress concentration by forming a bead between the curved and bent portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional T-shape welding is performed with straight base materials, then the welding process is simple, but stress concentration occurs due to small toe angles and non-welded root portions
Solution Approach 1:
The first base material is designed with curved portions instead of straight edges, creating a smoother transition zone that increases the toe angle of the weld bead. This curvature reduces stress concentration by distributing loads more evenly across the welded joint, thereby improving durability without significantly complicating the manufacturing process
Solution Approach 2:
The second base material is pre-bent to form a bent portion before welding takes place. This preliminary shaping ensures that the molten metal can properly fill the root portion during welding, eliminating non-welded areas and ensuring complete penetration. The pre-bent configuration is maintained throughout the welding process to achieve reliable stress distribution
2Strength
If the toe angle of the weld bead is increased, then stress concentration is reduced, but the welding process becomes more complex
Solution Approach 1:
By curving the first base material, the geometry naturally promotes a larger toe angle in the weld bead without requiring complex welding techniques. The curved surface guides the molten metal to form a more favorable angle, reducing stress concentration while maintaining manufacturing simplicity
Solution Approach 2:
The invention changes the geometric parameters of the base materials (curvature radius, bend angle) to optimize the weld bead formation. By adjusting these parameters, the toe angle is increased to improve stress resistance while keeping the welding process within standard manufacturing capabilities
3Productivity
If flare bevel welding is performed, then welding speed is maintained, but non-welded root portions occur due to gravity affecting molten metal
Solution Approach 1:
The second base material is pre-bent to create a configuration that facilitates proper molten metal flow into the root portion. This preliminary shaping compensates for gravitational effects during welding, ensuring complete penetration without requiring slower welding speeds or additional passes
Solution Approach 2:
The curved geometry of the first base material and bent geometry of the second base material work together to guide molten metal into the root portion. This geometric configuration overcomes gravity's detrimental effect on penetration while maintaining efficient welding speeds
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 design increases the durability of the welded joint by reducing stress concentration, as evidenced by a 55% decrease in maximum stress and a 51% increase in lifespan compared to traditional T-shape welding structures during durability tests.
Implementation Method 1
molten metal for welding sags downwardly under the influence of gravity
Data Source
AI summary
A welding structure of a T-shape welding joint in which a second base material is welded in a T-shape to a first base material may include the first base material including a first flat portion, a second flat portion, and curved portions formed between the first flat portion and the second flat portion; the second base material in which a bent portion is formed at an end of a main body portion such that the bent portion is disposed to face the curved portions of the first base material; and a bead disposed between the curved portions of the first base material and the bent portion of the second base material.