Dissolvable Polymer Fillers for Developing Hollow Complex Structures

Manufactures Light Weight, Load-Bearing Structures, Removing the Dead Weight, and Improving the Performance of Composite Structures

This manufacturing scheme deploys dissolvable internal support structures to develop lighter-weight structures with more complex geometries. Composite plies form the composite structures, stacking and bonding together. The strong and lightweight nature of the structures is highly desirable for a wide range of applications, including wind turbine blades, automotive structures, and aerospace vehicle components. The complexity of a complex structure design is often limited based on manufacturing techniques, making complex curvatures and angles difficult. It frequently requires joining multiple composite parts and using internal support structures.

During conventional manufacturing processes, the spar core within the structure must be packed with a filler material to support the load-bearing framework. This filler often becomes trapped under the skin, making removal impossible or damaging to the complex-geometry structure. Sometimes, the core material is useless and provides little structural strength to the final design.

Researchers at the University of Florida have developed dissolvable internal support structures for manufacturing complex structures. Flushing out the filler with water easily removes the material. Also, by avoiding mechanical removal of the filler, the dissolving process dodges the risk of damaging the load-bearing structure while extracting the filler. This frees space and weight within the complex structure, improving manufacturing efficiency and structural integrity.

Application

Dissolvable polymer filler to manufacture geometrically complex hollow structures

Advantages

• In aerospace applications, it eliminates the dead-weight internal filler material from the manufactured structure, boosting battery life by shaving off a sizeable percentage of the drone’s weight
• Dovetails with industry-standard molds already in use, avoiding drastic changes to the manufacturing process
• Flushes filler out of every corner of the final structure without damaging its integrity, enabling more exotic structural designs for higher performance

Technology

Typical mold-based manufacturing processes involve placing structural components such as stringers, spars, and ribs on and around a core made of filler material, such as balsa wood, honeycomb, or formed plastic. These structural components are composite materials and have little strength until the curing stage, so using filler is crucial despite contributing little to the shape or strength of the final product.

Unfortunately, the filler often becomes trapped inside structural components and acts as a dead weight. This manufacturing scheme removes the problem and uses a dissolvable polymer as the filler core. Filler removal from the final product only requires applying water, enabling complex and contorted structures to be manufactured.