الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
A comprehensive literature review is carried out in various aspects of
research particularly in hollow flange beams. HFBs are characterized by
their high torsional rigidity resulting in high stiffness and flexural
strength. It is found that the triangular hollow flange beams (THFB)
could achieve a good agreement with the basic requirements of the clean
design concept. It is being an important demand in all food processing
factories. However, the HFB production is discontinued by late 1990s
due to the manufacturing process difficulties.
Therefore, a new type of hollow flange beam known as Double Delta
Hollow Flange beam (DDHFB) is introduced using an alternative
manufacturing method which is based on riveted fastening process. In
addition, DDHFBs are providing a better structural performance than the
other previously investigated HFBs.
A finite element model is developed using ABAQUS / CAE 2016 finite
element package to investigate the flexural behavior and moment
capacities of simply supported rivet fastened DDHFBs. Both material and
geometrical nonlinearities were taken into consideration as well as the
geometrical imperfections. Arc-length combined with modified NewtonRaphson technique as an iterative solution method was adopted to obtain
the nonlinear static equilibrium solution. Verification of the finite element model using the quarter point loading
arrangement has been conducted by comparing the various experimental
results available in literature with the finite element results of LSB
sections as the DDHFB beams are newly introduced and experimental
research of DDHFBs are unavailable. The experimental results showed
an acceptable agreement in terms of the ultimate moment as well as the
load-deformation behavior and failure modes. Therefore, the model is
considered accurate enough to predict the flexural behavior of the
DDHFBs.
A comprehensive parametric study is carried out using an ideal model to
simulate the behavior of simply supported DDHFB sections subject to
uniform moment. The idealized boundary conditions are considered the
most critical case for the development of moment capacity design rules.
The best geometric configuration for the simplified DDHFBs is
investigated and a simple equation is proposed for the recommended
geometric configurations. The effects of flange width-to-flange depth
ratio and the flange depth-to- the web depth between the two hollow
flanges ratio on the flexural capacity of DDHFBs are studied. The results
of the finite element model are represented in charts and the effects of
these parameters are discussed.
Three groups of comparisons were conducted with the equivalent Isections with flat flanges in order to investigate the behavior and strength
of the new introduced DDHFB sections. The results indicate that the
DDHFBs have larger load-carrying capacities and stiffness compared to
equivalent I-sections in large unbraced spans, in addition to their benefits
in weight saving.
The suitability of current design rules in the Australian predictions
AS/NZS 4600 is investigated. In addition, previous proposed design rules
by other researchers for other similar HFBs having the same structural
performance of DDHFBs are also compared by finite element results of
DDHFBs. Moreover, comparison with current Direct Strength Method
(DSM) based design equation is carried out. The results indicate the suitability of DSM prediction in predicting the section moment capacity
of DDHFBs in all the buckling regions.
The effect of intermittent rivet fastening was investigated on the section
moment capacity of DDHFBs and a separate reduction factor was
proposed.