The distribution of flexibility and bending stiffness of beams is altered by the crack
size and location, the shape of beam cross-section, and the beam length. However, up
to now, most of the studies are mainly on the solid rectangular section beams,
rarely on the beams with variable cross-sections. A novel continuous stiffness
methodology for four classical cross-section beams is proposed based on fracture
mechanics and energy theory to estimate the effects of edge-crack depth
and location and the shape of cross-section on the distribution of bending
stiffness. First, the continuous bending stiffness of beams with shallow and
deep cracks is derived and solved using the Newton–Raphson technique.
The extent and degree of influence of crack depth, crack location, beam’s
length, and beam’s cross-section on the distribution of bending stiffness are
studied. Second, the correctness of the proposed continuous stiffness method
is verified using the experimental and theoretical data and the results of
the solid rectangular section beams in the literature. Finally, the natural
frequency ratios of the beams with different cross-sections, crack depths,
crack positions, and beam lengths are studied in detail using the precious
integration method (PIM), ANSYS element modeling (AEM) method, ANSYS
solid modeling (ASM) method, and Rotational Spring Modeling (RSM),
respectively. The availability and reliability of the proposed approach are verified
further. The study of the proposed continuous stiffness method may provide
some valuable references for modeling cracks of the different cross-section
beams.
Keywords
continuous stiffness, edge crack, distribution function,
natural frequency ratio, different cross section
Department of Marine Engineering and
National Center for International Research of Subsea
Engineering Technology and Equipment
Dalian Maritime University
Dalian, 116026
China
Beijing Key Laboratory of Pipeline
Critical Technology and Equipment for Deepwater Oil and Gas
Development
Beijing Institute of Petrochemical Technology
Beijing, 102617
China
Department of Marine Engineering and
National Center for International Research of Subsea
Engineering Technology and Equipment
Dalian Maritime University
Dalian, 116026
China
Department of Marine Engineering and
National Center for International Research of Subsea
Engineering Technology and Equipment
Dalian Maritime University
Dalian, 116026
China