Ultrasonic Load-Indicating Fasteners With Reactive Solder Bonding
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Solution Overview
Problem
Existing methods for measuring preload in mechanical connection components, such as screws, using ultrasound face challenges with temperature-dependent adhesive layers and chemical resistance, especially in harsh environments like offshore wind turbines, leading to unreliable and costly measurements.
Innovation Solution
A procedure involving a reactive layer system where the ultrasound converter is soldered directly to the connection element using a first and second solder layer, activated by heat to create a strong connection, allowing for reliable and resistant load-bearing components across various materials and sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an adhesive layer is used to bond the ultrasonic transducer to the connecting component, then the transducer can be easily attached, but the measurement reliability deteriorates due to temperature dependence and chemical degradation of the adhesive
Solution Approach 1:
A reactive layer is introduced as an intermediary between the ultrasonic transducer and the connecting component. This reactive layer, when activated, forms a permanent metallurgical bond that eliminates the problems of adhesive degradation while maintaining ease of attachment through the reactive bonding process
Solution Approach 2:
The bonding method is changed from adhesive bonding to reactive metallurgical bonding. This parameter change transforms the bonding mechanism from chemical adhesion (prone to degradation) to metallurgical fusion (temperature and chemically resistant), thereby improving measurement reliability
2Reliability
If a sputtering process is used to apply the piezoelectric ultrasonic transducer, then adhesive layers are eliminated, but the device complexity and production costs increase due to vacuum system requirements
Solution Approach 1:
A reactive layer serves as a mediator that enables direct bonding between the transducer and connecting component without requiring vacuum sputtering equipment. The reactive layer activates upon contact to form a metallurgical bond, eliminating complex vacuum systems while maintaining connection reliability
Solution Approach 2:
The complex vacuum-based sputtering system is replaced with a simpler reactive bonding process. The mechanical and equipment complexity of vacuum systems is substituted with a chemical reaction-based bonding method that achieves similar or superior connection reliability
3Reliability
If vacuum deposition systems are used for coating, then the transducer can be firmly attached, but the productivity decreases exponentially with increasing component size due to limited system volume
Solution Approach 1:
The reactive layer acts as a mediator that enables firm attachment without the constraints of vacuum chamber size. This allows large components to be bonded with the same reliability as small components, eliminating the exponential productivity decrease with component size
Solution Approach 2:
The bonding process transitions from a vacuum-based dimensional constraint to a chemical reaction process that is not limited by system volume. This dimensional freedom allows scalable production across component sizes without productivity penalties
4Ease of manufacture
If conventional adhesives are used in offshore environments, then the transducer can be attached, but the connection deteriorates due to poor resistance to salty sea air and chemical influences
Solution Approach 1:
The reactive layer serves as a chemically resistant intermediary between the transducer and connecting component. When activated, it forms a metallurgical bond that is highly resistant to salty sea air and chemical degradation, while the attachment process remains simple
Solution Approach 2:
The bonding interface becomes a composite structure involving the reactive layer that combines the benefits of easy attachment with superior chemical resistance. The reactive layer acts as a protective composite material resistant to offshore environmental degradation
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 provides a reliable, temperature-resistant, and chemically robust connection that maintains measurement accuracy even at high temperatures and in corrosive environments, reducing costs and increasing throughput for larger components.
Implementation Method 1
which, after activation, releases the heat required to create the soldered connection in an exothermic reaction
Implementation Method 2
a piezoelectric ultrasonic transducer is applied to the connecting element
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method for producing load-indicating connection components, wherein a connection element (10) and a piezoelectric ultrasonic transducer (20) are provided and interconnected. The method comprises forming a layer structure on the surface (14) of the connection element (10), which layer structure comprises, in this order, proceeding from the surface (14) of the connection element (10): - optionally a first solder layer (16); - a reactive layer (30); - optionally a second solder layer (22); and - the ultrasonic transducer (20). The reactive layer (30) is designed for an exothermic reaction by activation with heat, with electromagnetic radiation or with electric current. Subsequently, the ultrasonic transducer (20) is pressed toward the connection element (10) in order to produce a specified contact pressure, and the reactive layer (30) is activated. The invention also relates to a load-indicating connection component of this type.