John D. Whitcomb

Analysis of Hybrid Joints for Composite Tubulars

Walter Bradley; Marcel Sherman & Kanthikannan Srirengan (PhD students), Jae Noh (MS student)

Design of composite joints
Nonlinear analysis
Progressive damage modeling
Contact analysis
Time dependent behavior
Analysis of thick composites

OTRC's goal is to determine how to exploit the potential advantages of composites in the offshore oil industry. Development of efficient and dependable joints is essential if composites are to be used.

Detailed finite element models of potential joint configurations are being developed and analyzed to determine the basic behaviour of the joints and to thereby obtain insights for joint optimization. The commercial finite element code ABAQUS is being used for this study. We are developing our own custom constitutive module and linking it to ABAQUS using the UMAT facility. We are also developing new test specimens to characterize material properties which are critical for interference type joints.

NIST sponsored ATP projects

Advanced Computational Technology Initiative (Sandia National Laboratories)

Design of joints for thick wall composite structures requires detailed understanding of the material behaviour and innovative joint geometries. The current research helps lay a solid foundation for this challenge.

April 1995 to May 1998

Journal papers describing the following key technologies:

material homogenization, including distributed damage effects
computational modeling of progressive damage
design of joints which depend on mechanical interference
characterization of material properties which dominate the strength of joints based on mechanical interference
Regular meetings and phone calls with other team members for the NIST project "Manufacturing Composite Structures for the Offshore Oil Industry"
Presented paper on "Finite Element Based Degradation Model for Composites with Transverse Matrix Cracks," at the American Society for Composites meeting in October, 1996. The paper has been submitted to the Journal of Thermoplastics for publication.