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Multi-Material Joining

The multi-material joining project is an ongoing project that seeks to understand new joining technologies for binding different metals together. There is a need to join dissimilar materials together in a quick, easy and mechanically sound way. The multi-material joining project looks to understand these methods and how they will affect long-term performance of the material.

images of friction element weld, self-piercing rivet, resistance spot weldAbove L>R: friction element weld, self-piercing rivet, resistance spot weld

Proposal

Multi-material joining is one of our multi-industry projects. It is intended to continuously evolve as new material combinations, applications and joining technologies come into the marketplace. The program will be executed and managed by the CDME team, which performs engineering and manufacturing services for industry partners. CDME is looking for industrial sponsors to join us in evaluating and providing standards for joint architecture of dissimilar materials. Please contact John Bockbrader or Nate Ames to participate in the program. 

PROJECT GOALS

A full understanding of each joint evaluated for:

  • Corrosion response and predictive tool development
  • Strength (high and low strain rate)
  • Predictive fatigue life
  • FEA element for predictive solid modeling
  • Kinematic model for joint development
  • Building knowledge-based advisors to guide design engineers and joining process planners

THE TECHNOLOGY

The multi-material joining project will evaluate multi-material binding joints from a strength, adhesive and corrosion standpoint. These areas of investigation are important for the understanding of joining dissimilar materials in industrial applications so that long-term performance is maximized. The project has the ability to look at many different configurations of joining technologies and different material applications.

Ohio State's CDME has the unique capability to evaluate corrosion on several levels - through accelerated laboratory testing, on vehicle evaluation (both accelerated and real-time) and through modeling. This will allow us to develop accelerated corrosion testing based on real-world data for each joint to be studied. We will also be able to develop corrosion models that will allow engineers to predict joint performance.

Each joint will undergo extensive strength (low and high strain rate) and fatigue studies. These evaluations will lead to the development of kinematic models that will allow us to generate rules of thumb around joint architecture - how many joints are required and the ideal spacing. We will also use this information to develop FEA elements and their boundary conditions that will allow FEA analysis for strength, fatigue and crash-worthiness.

Initially, tests will focus on tack joint technology, primarily using ridged nails. As such, a ridged nail is driven through multiple layers of material creating a joint that can be as strong as a resistance spot weld (RSW). For added strength, an adhesive layer is used in conjunction with the tack. This kind of joint is ideal for creating a strong adhesive bond. Additionally, the insertion process creates a consistent bond line for the adhesive without the need to remove the adhesive at the joint location.

KEY FEATURES AND BENEFITS

  • Adhesive layer testing increases stability and strength of the joint
  • Understanding corrosion at the joint site can enhance safety of the application
  • Expanded options for joining dissimilar materials become available
  • Corrosion studies can increase durability and lifetime of joined materials

picture of tack joint technology using ridged nailsTack joint technology using ridged nails