Applications

Aerospace, automotive, marine, construction, energy, biomedical, and recreational sports equipment applications.

Target Problems

Standard inserts used to connect sandwich composite panels can experience premature joint failure due to stress concentrations caused by abrupt changes in stiffness. They often require post-cure machining and may not provide sufficient contact with panel components, which can limit strength and overall performance.

Solution

This technology uses additively manufactured inserts that are integrated into sandwich composite panels during the cure cycle. The insert geometry enables improved flow and distribution of potting material, enhances adhesion to the facesheets, and allows gradual changes in stiffness to reduce stress concentrations. The result is a fastening solution that provides higher strength, improved structural performance, and reduced post-processing requirements.

Key Benefits

• High Temperature Performance: Thermal stable and durable in extreme environments
• Increased Maximum Force: >200% in single-lap shear tests and >50% in pull-through tests compared with standard inserts.
• Superior Energy Absorption: Improvement of >550% in single-lap shear tests and >60% in pull-through tests compared with standard inserts.
• Enhanced Stiffness: >7% increase in stiffness in panels connected with these inserts, contributing to better load distribution and reduced risk of joint failure.

Watch this video to learn more!

About this Technology

The inserts are manufactured using additive manufacturing methods that enable internal features not
available with standard inserts. These features allow potting material to flow around the insert and into
adjacent core regions while enabling the panel facesheets to overlap and adhere to the insert. The design
also allows stiffness to be adjusted gradually, helping reduce stress concentrations within the joint.

Stage of Development 

Experimental and numerical analyses have been completed to quantify improvements.

Partnering Opportunity 

This invention is looking for partner apps with manufacturers that fabricate sandwich composite
components.

Intellectual Property 

Patent pending. Protected and managed by the UWM Research Foundation.

Inventors

Rani Elhajjar, UWM Professor, Civil and Environmental Engineering