A comparison of energy absorbing capabilities of paper and steel structures subjected to progressive failure under free falling objects

An inverted paper cup of 0.26 mm thickness was subjected to deformation under a freely falling steel ball at a velocity of 2.77 m/sec. The deformed features of the paper cup were measured. The dynamic loading event was simulated using piecewise linear plasticity material model in LSDYNA. Deformed shape of the paper cup in finite element model matched closely with experimental results with ignorable small discrepancies. The paper cup was able to absorb all the kinetic energy of the falling steel ball for the above mentioned falling speed and the ball did not bounce out of the cavity generated by the impact. In LSDYNA a similar size steel cup was also subjected to a freely falling ball with same speed and the energy absorbed was compared to the energy absorbed by the paper cup. It was found that under similar conditions a paper cup would undergo a significant progressive failure and absorb all the energy of the falling object

Numerical analysis on materials energy absorbing capability under gravity loading impact

Energy absorbers are systems that convert kinetic energy into other forms of energy, such as pressure energy in compressible fluids, elastic strain energy in solids, and plastic defonnation energy in defom1able solids. The process of conversion for plastic defonnation depends, among other factors, on the magnitude and method of application of loads, transmission rates, defonnation displacement pattems, and material properties. The applications of defonnable energy absorbers have been paid serious attention for several decades, for the means of safety. The aim is to minimize the impact by controlling the deceleration pulse during impact, i.e. extending the period of dissipation of kinetic energy. Cushioning devices on vehicle bumpers, crash retarders in emergency systems of lifts, and some crash barriers used as road blocks are everyday examples. The vital application of this work is reliability of energy to absorb massive landing force, for instance the missile safeguards when landing on the ground. The high energy absorbing ability can practically applied into rocket system for sending the chips or any other important materials to the space or far-distant place, thus protecting the chips from damag

Simulation setup of pipe whip impact

The safety of pipe whip is related issue for nuclear power and chemical plants, where pIpes are often used to transport fluids at high pressure and high temperature. Simulation analysis for empty pipe and liquid filled pipe are conducted in this study. The model was made of simple pipe whip system which enables the missile pipe to hit the target pipe at an angle of 90° and also 55° oblique impact. The simulation setup is done by LS-DYNA which is an developed by the Livennore Software Technology Corporation (LSTC). It is a highly nonlinear transient dynamic finite element analysis using explicit time integratio

Simulation results of pipe whip impact at 55° angle

The safety of pipe whip is related issue for nuclear power and chemical plants, where pIpes are often used to transport fluids at high pressure and high temperature. Simulation analysis for empty pipe and liquid filled pipe are conducted in this study. The model was made of simple pipe whip system which enables the missile pipe to hit the target pipe at an angle of 55° oblique impact. The simulation setup is done by LS-DYNA which is highly nonlinear transient dynamic finite element analysis using explicit time integration. The results show the defonnation occurred in the pipe whip at different degrees of impact

Experimental results of liquid slosh in a cylindrical tank with different fill levels

The fundamental properties of slosh could be effectively investigated through laboratory experiments under controlled conditions. Such experiments can provide considerable insight into the fluid slosh and associated forces and moments. The nlajority of the experimental investigations on the fluid slosh have been conducted in model tanks which are small in size compared to the full scale tanks of cross-section area in the order of 3.5 mn2. The cross-sectional areas of the model tanks employed in the reported studies were in the order of 0.2 m' [I-31. Since the similarity of sloshing fluid flows is very complex, the slosh behavior would be expected to differ for different tank sizes. Moreover, some of the reported slosh studies were limited to measurements of hydrodynamic pressure at given points or only one component of the slosh forces. The stability of a road tank vehicle, however, is strongly dependent on the resultant slosh forces and moments arising in all the translational and rotational axe

Experimental setup of pipe whip impact

Pipe whip is a safety related issue for nuclear power and chemical plants, where pipes are often used to transport fluids at high pressure and high temperature. Experiment works for empty pipe and liquid filled pipe are needed in this study. The model was made of simple pipe whip system which enables the missile pipe to hit the target pipe at an angle of 90° and also 55° oblique impact. The possible damages occur on the target pipe when the missile pipe hit it at certain velocity depend on the different mass of dropper and different diameter ofthe target pipe. Copper pipe is used as the target pipe and steel as the missile pip

Damage assessment of liquid filled container subjected to free fall on rigid steel plate

Chemicals can be a great threat to society and to the environment, despite its wide usage III industrial applications. Extra precautions have to be taken into account, considering the increasing numbers of accident cases involving chemical-transp0l1ing tanks. Precautions should be taken especially when transporting chemicals of radioactive nature. Should any spill of such chemicals occur, its effects on the environment and human life can be catastrophic. In tel111S of passive safety, the tank designer has to study the probable effect on the tank body such that the transporter gets involved in a crash, thus enhancing the design. In this project, we have performed drop testing on liquid filled containers. The defonnation of the specimen was observed after the impact. Prediction for the defonnation OCCUlTed on the container after being dropped through a 6 meter pipe was taken as the result. The damage assessment of the waterfilled container is very important for some industries in order to avoid danger that might occur to the container when it accidently falls. Some chemical liquids can pose great danger to the environment. Therefore, if we can predict something before it happens, we can use many possibilities to avoid it

Numerical and experimental results of liquid slosh in a partially filled cylindrical tank

Several experiments with different water levels were conducted to monitor the effect of water slosh in the container tank. This experimental study on fluid slosh was conducted to validate the results of the numerical models. The observation of the experimental results shows that strain gage-1 experienced compression strain at the top of the tank, while strain gage-2 experienced tension strain at the frontal area. The unit of the strain is displayed in pdm. From this experiment, the values for strain gage-1 is quite lower than strain gage-2.This big different is due to strain gage-2 in the frontal area is experience more forces and moments compared to the strain gage- 1 at the top of the tank

Experimental results of pipe whip impact

Pipe whip is a safety related issue for nuclear power and chemical plants, where pipes are often used to transport fluids at high pressure and high temperature. Experiment works for empty pipe and liquid filled pipe are needed in this study. The model was made of simple pipe whip system which enables the missile pipe to hit the target pipe at an angle of 90° and also 55° oblique impact. The results of the experiments show the possible damage and failure of different types of pipe whip with different fill conditions. 2