Isotropic dilation of wrapped 3D-printed carbon fiber cylinders with lap joints

Overview

This study presents an isotropic dilation loading framework as an alternative methodology for characterizing burst properties of composite cylinders without requiring high-pressure test facilities. Carbon fiber cylinders with lap joints were manufactured via integrated 3D printing and manual fabrication, then subjected to radial expansion loading via axial compression of incompressible rubber pucks until failure. The approach combines experimental testing with analytical validation and full-field strain measurement techniques.

Methods and approach

Carbon fiber composite cylinders with lap joints were fabricated using an integrated 3D printing and manual shaping approach to produce thin-shell structures. Ring samples were positioned on donut-shaped incompressible rubber elements that expanded radially upon axial compression with oversized indenters. Loading was applied until ultimate failure under controlled conditions. Mechanical characterization incorporated analytical solutions, full-field strain measurements, and biaxial strain gauges positioned to capture local strains within the composite rings. Testing encompassed both quasi-static and dynamic loading regimes to evaluate strain-rate effects.

Key Findings

Lap joint failure occurred at hoop strains of approximately 1.77 mε, with results demonstrating close agreement with analytical solutions within acceptable deviation ranges. Full-field and local strain measurements confirmed the strain-dominated failure mechanism governing the composite system. Dynamic loading conditions produced more severe damage modes compared to quasi-static testing, including geometric deformation and peripheral laminate failure. The isotropic dilation framework successfully characterized burst behavior without requiring dedicated high-pressure test facilities.

Implications

The isotropic dilation loading methodology demonstrates technical feasibility as a scalable alternative to conventional burst pressure testing for composite cylinders. The approach reduces infrastructure requirements and associated costs while maintaining measurement accuracy through analytical validation and multi-channel strain instrumentation. Results support further development of predictive computational models and standardized testing protocols leveraging this framework. Dynamic loading data indicates that strain-rate effects produce qualitatively distinct failure modes, suggesting implications for application-specific design considerations in composite cylinder engineering.