Papers by Keyword: AUTODYN

Abstract: Reinforced concrete (RC) is the most preferred construction material for the civilian structural construction such as building and bridge because it is economical to build and possesses high strength. There have been several verified numerical studies on RC, but most have all been limited to the scope of a small rectangular or small square RC panel clamped at the edges. As a result, there is still a need for a complete RC structure for example RC wall with its foundation to represent as a single stand structure. With available validated complete RC structure experimentally and numerical data on blast pressure profile, detail numerical study is possible to investigate in depth. In AUTODYN commercial software, arbitrary Lagrange Euler (ALE) solvers are used to analyse the interaction between air and RC wall structure. The RC walls were built with the same moment resistance but a different hooked direction on vertical flexural steel reinforcement into the foundation. The numerical result indicated that in the hooked-in direction, the average strain at the back side of the wall peaked at 1.0625×10-3 at first 5 msec after impact, which is half of what it was in the hooked- out direction. Furthermore, the numerical simulation coincided with the experimental findings, where the proper steel arrangement for the RC wall subjected to blast was hooked-in.

Abstract: Cutting iron bars using a gas cutting machine is indispensable inside puddles of pier foundations. However, gas explosive accidents constantly occur as a result of the leakage of gas. It is necessary to perform specialized and systematic evaluations on structural stability, such as internal stress of the support structure, because the structural stability dominates the explosion and the collapse possibility of the structure. In this study, a structure-fluid interaction analysis was performed using an explosion commercial program, 2D/3D AUTODYN, to apply engineering numerical analysis technology to analyze the fracture behavior. The structural stability of the supporting structure in puddles was evaluated.

Abstract: Recycled rubber materials are one of cheap and suitable materials for energy absorbers in protective structures. Standard tests of elastomers in uniaxial or biaxial tension is not suitable and efficient for energy absorbers made of recycled car tires. Simple compression test and simple impact test are described material properties from those tests are determined and compared with simulation in ANSYS/AUTODYN.

Abstract: This paper describes influence of different mechanical properties to the concrete penetration resistance. The resistance is evaluated on the basis of the presented experimental program. In the experiment, non-deformable ogive-nose projectiles with diameter of 7.92 mm and mass of 8 g with impact velocity of about 700 m/s were hitting center of the specimens. Determination of the concrete penetration resistance was than based on projectile residual velocity obtained from high-speed camera record. The specimens were made from high strength concrete, steel fiber-reinforced concrete, ultra-high performance concrete and ultra-high performance fiber-reinforced concrete with different fiber content. The concrete penetration resistance was evaluated on total 32 specimens. Influence of mechanical properties, addition of coarse aggregate and steel fibers were discussed. Mechanical properties of the tested materials were investigated on total 125 specimens. Data from the measurements were used for creation of new RHT concrete models in Autodyn. In order to confirm experiment's setup and results, numerical analysis was performed in Autodyn. Results of the numerical simulations were compared to the experimental program.

Abstract: In order to develop an active protection system for armored vehicles, the launching process of a cylindrical rod-shaped interception projectile was analyzed. The variations of the movement and the velocity of the interception projectile according to the mass ratio of the interception projectile to the LX-14 explosive were simulated using AUTODYN. Simulated results showed that the mass ratio of the interception projectile to the explosive plays a dominant role in determining the final velocity of the interception projectile.

Abstract: Generation and transmission of blast waves in real terrains is of major importance for risk analysis procedures involving accidental explosion scenarios. This paper aims to show the approach to addressing air pressure waves from explosions using empirical formulas and compare them with numerical computations, which is solved using the computational program AUTODYN. Simulation of a simple model of the building is presented in the interaction with the air pressure wave caused by the explosion, which is initiated at a distance of 30 meters from the front of the building. The explosion process will be shown in 2D axial plane which is then remapped into Eulerian multi-material 3D space using the interaction of the rigid obstacles. The weight of 1000 kg TNT charge is used, which is located one meter above the ground and represents the explosive placed in a car in accordance with FEMA requirements. The effects of the protection structures are investigated.

Abstract: To date, the highest pump pressure available in market is 648 MPa from FLOW International Corp. Cutting with ultra high pressure reduces abrasive usage, faster cutting speed, increased depth of cuts and increase efficiency. This research explores the possibility of applying pressure exceeding 1000 MPa to push pure water to cut solid objects. 10 grams of PE4 explosives are exploded in a confined chamber with a rectangular opening. Simulations in designing the blast test jig are discussed. Simulations are done using Autodyn software. The simulation aims to get the optimum geometry that can give the highest pressure at nozzle exit. Two materials are chosen to cut; stainless steel 304 and aluminum 1100. Simulations show the optimum blast test jig can cut aluminum and stainless steel at certain thickness.

Abstract: Needing to analyse fragment’s destructive effect for military researching purpose, it is produced after armour-piercing warhead penetrate target. How to reduce physical test expense and acquire believable researching result at the same time have been puzzled problems that must be solved as soon as possible. Discussing techniques of fragment produced in armour-piercing warhead penetration process with the way of numerical simulation based on AUTODYN, it is a program that analyses dynamics in this paper. Techniques mainly include the Lagrange, the SPH, the Lagrange combining with the SPH and the Lagrange combining with restriction invalidation, at the same time, analysed different technique’s merit and demerit by establishing the numeric simulation model of armour-piercing warhead destroying target and obtaining simulation result. By researching the technique of making numeric fragment, establishing favorable base for researching armour-piercing warhead destroying mechanism.

Abstract: Recently, the damaged building and loss of life have been increasing by man-made disasters. In this study, the blast resistance performance of fiber reinforced concrete against explosion was evaluated by the emulsion explosive and AUTODYN. The concrete without fiber was penetrated by emulsion explosive of 4605 kJ/kg and its back side was fractured heavily. The concretes with PVA, PE and Steel fiber have a higher blast resistance than that of concrete without fiber. Consequentially, the blast resistance of concrete was analyzed from viewpoint of fracture mode by AUTODYN and it was concluded that the fiber content is a beneficial for the blast resistance performance of concrete.

Abstract: Concrete when subjected to a blast loading from a close-in detonation will experience spalling due to formation of tension waves on the opposite face of the concrete panel. The spalled concrete may be ejected at high velocity causing undesirable effects to occupants. Tests using 1/2kg TNT blocks were conducted on 100mm thick concrete panels to study the effects of spalling and whether the spalled materials can be arrested using a sprayed-on polymeric coating. From the tests, it was observed that without the sprayed-on polymeric coating, extensive spalling occurred. However, with just a 3-4mm thick layer of sprayed-on polymer, the spalled materials were arrested and contained. Numerical models of the reinforced concrete slab were created using Autodyn 2D and the results of the simulation were compared to observations from the tests. There was good correlation between the test results and the simulation results as the size of the crater, both front and back, on the concrete slab were rather similar.