Abstract: This paper presents the effect of corrugation profile
geometry on the crushing behavior, energy absorption, failure
mechanism, and failure mode of woven roving glass fibre/epoxy
laminated composite tube. Experimental investigations were carried
out on composite tubes with three different profile shapes: sinusoidal,
triangular and trapezoidal. The tubes were subjected to lateral
compressive loading. On the addition to a radial corrugated
composite tube, cylindrical composite tube, were fabricated and
tested under the same condition in order to know the effect of
corrugation geometry. Typical histories of their deformation are
presented. Behavior of tubes as regards the peak crushing load,
energy absorbed and mode of crushing has been discussed. The
results show that the behavior of the tube under lateral compression
load is influenced by the geometry of the tube itself.
Abstract: Study fluid flow and heat transfer characteristics of
microchannel in a primary Cross-corrugated(CC) surface recuperators
with corrugations and without corrugations, using CFD method. The
pitch-over-height ratios P/H of Cross-corrugated (CC) surface is from
1.5 to 4.0, included angles β=75º. The study was performed using CFD
software FLUENT to create unit model and simulate fluid
temperature, velocity, heat transfer coefficient and other parameters.
The results from these simulations were compared to experimental
data. It is concluded that, when the Reynolds number is constant, if
increase P/H, j/f will decrease, also the decreasing trend will become
weak. Under the condition of P/H=2.2, if increase the inlet velocity j/f
will decrease; in addition, the heat transfer performance in surface
with corrugation will increase 10% compared to that without
corrugation. The study results can provide the basis to optimize the
design, select the type of heat transfer surface, the scale structure, and
heat-transfer surface arrangement for recuperators.
Abstract: Fracture process in mechanically loaded steel fiber
reinforced high-strength (SFRHSC) concrete is characterized by
fibers bridging the crack providing resistance to its opening.
Structural SFRHSC fracture model was created; material fracture
process was modeled, based on single fiber pull-out laws, which were
determined experimentally (for straight fibers, fibers with end hooks
(Dramix), and corrugated fibers (Tabix)) as well as obtained
numerically ( using FEM simulations). For this purpose experimental
program was realized and pull-out force versus pull-out fiber length
was obtained (for fibers embedded into concrete at different depth
and under different angle). Model predictions were validated by
15x15x60cm prisms 4 point bending tests. Fracture surfaces analysis
was realized for broken prisms with the goal to improve elaborated
model assumptions. Optimal SFRHSC structures were recognized.