Session: DA-04-01 Inelastic, Nonlinear, and Limit Load Analysis
Paper Number: 154751
154751 - Crushing Analysis of Circular Tube With Local Thickness Reduction Between Wedge Indenter and Rigid Plane
Abstract:
Offshore pipelines are susceptible to both corrosion induced thickness reduction and external inference load
from anchors or dropping objects.
The deformaton modes and energy absorption properties of defected rings have been rarely
studied. This paper presents a combined experimental, FEA and analytical analysis of crushing
of circular rings with local thickness reduction between a wedge-shape indenter and a rigid plane.
Short-width aluminium defected ring specimens were manufactured by CNC milling to avoid residual stress
and experimentally crushed under a top wedge of 90 deg included angle. The tensile tests were carried out to obtain the material hardening parameters. A python script in Abaqus was compiled to allow automatic parametric modelling and analysis enabling
extensive parametric analysis under plane stress condition.
The active yielding region visualization was employed to illustrate clearly the evolution of plastic regions.
Parametric analysis was presented for corrosion depth, angular extent, 0 or 180 deg orientations and material hardening.
For 180 degree orientation case, the collapse mechanisms were distinctly different in early and later phases due to the appearance of top plastic hinge in the second phase. Both FEA and experimental results agreed well.
Analytical formulations by rigid plastic model are presented for crushing phases with initial elastic phase predicted well by Castigliano's theorem.
Initial phase prediction agreed exactly with FEA or experimental results. While the accuracy of analytical formulation was shown to signicantly depend on the hardening property: when hardening is weak, the plastic hinge is more localized and the collapse mechanism is well-predicted and when hardening is larger, plastic region was extended with considerable length.
The effective plastic region length was quantitatively extracted as the active yielding region from FEA and in-depth parametric analysis was presented for the plastic region length variation pattern for different hardening level and geometric parameters.
Interestingly when 180 deg oriented when corrosion angle is small, some separation at bottom occurs. We showed that this phenomenon was affected by the friction by FEA by comparing the results at the zero and unity friction coefficients.
Finally the total absorbed energy curves are plotted showing the signicant effect of local thickness reduction and orientation.
This paper should enhance the understanding of crushing behavior of defected short-length tube or ring under plane stress state and applicable to structural integrity assessment for estimating the allowable impacting kinetic energy.
Presenting Author: Sunting Yan Zhejiang Academy of Special Equipment Science
Presenting Author Biography: Sunting Yan obtained PhD degree on the topic of offshore pipeline stability and maintenance in Zhejiang university in 2017, worked as post-doc in Zhejiang university under the supervision of Prof. Zhijiang Jin who is a renowned expert in the field of valve optimization and design in China and since then worked as a full-time employee
in Zhejiang academy of special equipment science in Hangzhou as a researcher on the topic of pipeline integrity maintenance and non-destructive testing techniques. Sunting Yan has published more than 20 journal papers indexed in SCI&SCIE database and has wide interest in stability, burst failure and experimental apparatus construction and measurement methods in pressure vessel and piping domain.
Authors:
Sunting Yan Zhejiang Academy of Special Equipment ScienceYonggui Chen Zhejiang academy of special equipment science
Ping Tang Zhejiang academy of special equipment science
Chenfeng Guan Zhejiang academy of special equipment science
Wei Zhang Zhejiang academy of special equipment science
Jin-Yuan Qian institute of process equipment,Zhejiang University
Kan Sheng Institute of process equipment,Zhejiang university
Crushing Analysis of Circular Tube With Local Thickness Reduction Between Wedge Indenter and Rigid Plane
Paper Type
Technical Paper Publication