Hypoeutectic Steel Anchor Stud for Cracked Concrete
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Solution Overview
Problem
Existing anchor studs for attaching objects to concrete structures face challenges such as high cost due to the use of stainless steel, which is prone to galvanic corrosion and stress corrosion cracking, especially in cracked concrete, and cold welding or galling issues that complicate anchoring and detection.
Innovation Solution
An anchor stud made from hypoeutectic steel with a Vickers hardness between 218 HV and 290 HV for both the wedge and sleeve elements, which are formed from medium carbon steel, ensuring similar properties and preventing cold welding or galling, while maintaining anchoring integrity in cracked concrete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stainless steel is used for the sleeve element to provide durability and anchoring capability in cracked concrete, then reliability is improved, but cost increases significantly
Solution Approach 1:
The patent changes the material parameter from stainless steel to hypoeutectic steel with specific carbon content (0.20-0.50% C) and hardness (100-230 HB), achieving comparable reliability at lower cost by optimizing the chemical composition and mechanical properties of the alternative material
Solution Approach 2:
The patent replaces expensive stainless steel with a more economical hypoeutectic steel material that achieves the required performance at lower cost, making the anchor stud economically viable for widespread use in cracked concrete applications
2Adaptability or versatility
If dissimilar metals are used for wedge and sleeve elements, then material selection flexibility is improved, but galvanic corrosion occurs at interface zones
Solution Approach 1:
The patent applies homogeneity by making both the wedge and sleeve elements from the same hypoeutectic steel material with matching chemical composition and mechanical properties, eliminating galvanic corrosion at the interface while maintaining material selection flexibility and adaptability
3Strength
If highly cold worked stainless steel is used to increase strength, then strength is improved, but stress corrosion cracking is exacerbated
Solution Approach 1:
The patent changes the material composition parameters by using hypoeutectic steel with optimized carbon content (0.20-0.50% C) and controlled hardness (100-230 HB), achieving the required strength while significantly improving resistance to stress corrosion cracking compared to highly cold worked stainless steel
Solution Approach 2:
The patent converts the potential harm of using non-stainless steel (susceptibility to corrosion) into a benefit by selecting hypoeutectic steel that is inherently more resistant to stress corrosion cracking in calcium chloride and sulfite environments, while still providing the necessary mechanical strength
Data Source
Figure 1
AI summary
An anchor stud includes a stud portion including a body portion having a first end that extends to a second end though an intermediate portion. A wedge member is operatively coupled to the second end of the stud portion. The wedge member includes a body having a generally frustoconical profile and is formed from a material having a Vickers hardness of between about 218 HV and about 290 HV. A sleeve element is positioned on the stud portion at the second end adjacent the wedge member. The sleeve element is formed from a material having a Vickers hardness of between about 218 HV and about 290 HV.