Papers by Author: Guo Xing Lu

Abstract: This work studies the large deformation behaviors of a re-entrant honeycomb subjected to the quasi-static tensile loading by employing the finite element (FE) package ABAQUS 6.11-2. The size effect of FE models is firstly investigated. Then, the deformation mechanism and stress-strain curve of a re-entrant honeycomb are discussed. Finally, the plastic Poisson’s ratio is calculated from the true strain and presented.

Abstract: In this study, hollow square carbon fibre reinforced plastic (CFRP) tubes and aluminium sheet wrapped CFRP tubes have been axially crushed at a quasi-static loading velocity of 0.05 mm/s. A specially designed and manufactured platen with four cutting blades was used to cut and crush these two tubular structures. The four cutting blades had height of 5 mm and width of 3 mm with round tip to reduce the initial peak force and achieve a stable crushing deformation mode. Notches at one end of each tube were utilized to control the location of initial failure. The crashworthiness characteristics of hollow CFRP tubes and aluminium sheet wrapped CFRP tubes with notches that crushed by the platen with cutting blades were compared with those of tubes that crushed by a flat platen. Experimental results showed that using the platen with blades to crush the specimens with notches exhibited more stable deformation mode than the specimens without notches. Mean crushing force, energy absorption and specific energy absorption (SEA) increased when CFRP was wrapped with aluminium sheet and crushed by the platen with blades. The increase of average value of mean crushing force, energy absorption and specific energy absorption of aluminium sheet wrapped CFRP tube and crushed by the platen with blades are 16.5%, 17.3% and 5% respectively more than those for hollow tubes that crushed by a flat platen.

Abstract: Rock movement caused by external explosion loading can damage the nearby tunnel or cavern.To avoid damage, energy absorbing bolts with high load-displacement and large energy absorptioncapacities are required. The deformation and friction of the bolt absorb energy during the rock movementand preventing the structure from damage. To maximize the energy absorption capacity in the limitedspace inside the borehole, we developed a new bolt that utilizes the friction and plastic deformation ofthe sleeve. To develop the new bolt, FE simulation in Abaqus was used to improve designs beforefabrication. Two prototypes of the new design was fabricated and tested by static pull test. The resultsshowed the bolts yielded in the desired way. The experimental results prove the new bolt is capable ofabsorbing large amount of energy and accommodating large displacement.

Abstract: A full scale finite element (FE) analysis has been conducted on aluminum hexagonal honeycomb to investigate its deformation mechanism and mechanical performance under combined compression-shear loads. ANSYS LS/DYNA software has been employed in this numerical study. The honeycomb FE model has the same dimensions (cell size and cell wall thickness) as those used in the previous experimental study. The FE model has been verified by the experimental results. A good agreement between the experimental and numerical results has been reached. This numerical analysis facilitates the measurement of the vertical and horizontal forces applied to honeycomb specimens. The effects of strain rate, plane orientation of cell walls and loading angle on the plateau stress and energy absorption of honeycomb specimens under combined compression-shear loads were investigated.

Abstract: Failure of aluminium foams due to dynamic indentation and penetration is very common in their application such as light-weight structural sandwich panels, packing materials and energy absorbing devices. This requires a sound understanding of deformation and energy absorption mechanisms of the aluminium foams as well as the effect of impact velocity. In this study, a finite element analysis using ABAQUS is conducted for the dynamic indentation/penetration process of aluminium foams under a rigid flat-headed indenter. The indenter is pushed into the foam either at a constant velocity or with an initial velocity. Two mechanisms exist: compression of the foam ahead of the indenter and fracture along the indenter edge. Effect of impact velocity is noted on the size of a localized deformation and the total energy absorbed.