Papers by Keyword: Compression Load

Abstract: Corrugated cardboard has multilayer construction that produces rigid, durable, and worthy material for shipping heavy goods or hazmat. The numerous advantages offered have made it a worldwide staple in the warehousing, packaging, and transportation industries. Unfortunately, studies on corrugated cardboard’s mechanical properties and behavior are still limited due to the complexity of structures and testing procedures. The present work investigates corrugated cardboard’s mechanical properties and behavior by conducting uniaxial tensile and compressive tests. Three different testing directions in x, y, and z-axes were applied on AA-flute double-wall (AA/F-DW) or virgin pulp paper Bi-Wall corrugated cardboard. The stress-strain curve is measured and evaluated to obtain the mechanical properties, i.e., yield strength and ultimate strength. The result shows that corrugated cardboard has linear and non-linear mechanical behavior or elastic-plastic regions under those different directions. Moreover, the flute on the corrugated cardboard gives jaggedness to the stress-strain curve and makes the material more elastic, more durable, and has better absorbing energy capacity. This finding could be used to design any products, such as a packaging frame made of corrugated cardboard, where the strength of the structure could be predicted based on the mechanical properties and behavior.

Abstract: It is difficult to repair the damage cartilage by itself when cartilage is injured. Cartilage tissue engineering is an ideal treatment method to repair cartilage defects, but at present, the repair has some uncertain effects which is caused by the mechanical states of the repaired region. Under the compression, mechanical behaviors of the repaired full-thickness defect were analyzed by means of the digital correlation technology. Experiments show that in the direction of vertical cartilage surface, the maximum compressive strain of artificial cartilage is 1.7 times higher than the normal host cartilage at 5.1% compression, and it is 1.4 times higher than the normal host cartilage at 25.6% compression. In parallel to the cartilage surface direction, the interface appears compressive strain and the host cartilage near the interface presents a smaller tensile strain. In the aspect of shear strain, direction of shear strain at the junction changes to the opposite direction with the compressive increase.

Abstract: The work is devoted to the problem of role of ambient factors (external electromagnetic field, in particular) in the process of ageing of mechanically burden nonmetallic solids (rocks). A specific research point is the effect of temporary activation of Acoustic Emission (AE) of rocks specimens during action of EM field pulses applied externally. Extended experimental studies of responses of AE have been conducted to evince the changes in defects accumulation process in loaded specimens due to external power impacts (EPI). The experiments have been held on noiseless rheological machines available at Bishkek Geodynamic Research Center - RS RAS. We have tested a number of specimens made of different materials and analyzed the temporal dependence of AE activity during exposure in electric field and crossed electric and magnetic fields; the compressive load being constant. The effect of AE stimulation by power pulses (triggering) has been verified. The obtained results allow to distinguish two kinds of AE activation. The first kind involves simultaneous well correlated growth of numbers of minor and major AEs (so-called selfconsistency of temporal plots of activity of different range acoustic events). The second kind represents dissimilar variations: the increment of activity of minor energy AEs, but the decrement of those of major energy. The first kind of solids material responses to EPI is prevailing when the compressive loads is under 0,85 of fracturing value. The episodes of dissimilar AE responses may signify that electromagnetic control of defects accumulation process inside rocks is possible, in principle.