Frequency domain analysis allows LS-Dyna users to explore capabilities such as frequency response function, steady state dynamics, random vibration, response spectrum analysis, acoustics BEM and FEM, and fatigue SSD and random vibration. You can use these capabilities for applications such as NVH, acoustic analysis, defense industry, fatigue analysis and earthquake engineering.
ls dyna tutorial ebook 12
Ansys LS-DYNA has two different classes of mesh-free particle solvers: continuum-based smooth particle hydrodynamics (SPH), and discrete particle solvers using the discrete element method (DEM), the particle blast method (PBM) and the corpuscular particle method (CPM). These solvers are used in various applications like hypervelocity impacts; explosions; friction stir welding; water wading; fracture analysis in car windshields, window glass and composite materials; metal friction drilling; metal machining; and high-velocity impact on concrete and metal targets.
The smoothed particle Galerkin (SPG) method is a new Lagrangian particle method for simulating the severe plastic deformation and material rupture taken place in ductile material failure. The Peridynamics method is another compelling method for brittle fracture analysis in isotropic materials as well as certain composites such as CFRP. These two numerical methods share a common feature in modeling the 3D material failure using a bond-based failure mechanism. Since the material erosion technique is no more necessary, the simulation of the material failure processes becomes very effective and stable.
The results are interpreted by using LS-PREPOST to analyze the energy absorption characteristics during crash for different materials at a velocity of 30mm/ms which is approximately 108 km/hr for the duration of 15 ms. The project is carried out for three cases and they are different material models, constant velocity for particular selected material model and using same thickness for particular material model. With the help of LS-DYNA codes nonlinear dynamic contact analysis by using different materials can be done effectively and accurately. The results are found that steel material absorbs maximum internal energy of 88.25% followed by aluminium and plastic materials with 82.28 and 72.23% respectively. This is because steel has high Young's Modulus when compared to aluminum and plastic material and also impact force distribution is uniform in steel material.
The run time of file is 15ms. The results are plotted for the energies absorbed by the fascia in 15 ms. DT min is the interval in which the codes are generated in processing the file in ls-dyna. DT is the time step value. It is the minimum time taken by the sound wave for travelling from one end to other of the shortest element. It is also used in plotting the graph i.e. for every 0.1 interval a point on the graph is plotted. Decreasing the value below 0.1 increasing the smoothness of the curve but at the same time increases time.
Note: As in the other tutorials, all menu items that need to be selected will be preceded by a maroon right arrow: >User action. Mouse buttons are indicated as follows: -- 1B = First (left) button -- used for selecting items-- 2B = Second (middle) button -- used for "OK"-- 3B = Third (right) button -- used for View Manipulation & pop-up menusNormally 1B is used, unless otherwise. Table Of Contents SectionPage Step1. Import Nastran Deck. 3 Step2. Check Model Statistics. 4 Step3. Modify Part.. 5 Step4. Modify Material Properties. 6 Step5. Create X-Y Plots. 7 Step6 . Import X-Y Plots. 8 Step7 . Penetration checking. 9 Step8 . Penetration Fixing. 10 Step9 . Quality Check On Element Length Criteria. 11 Step10. Fix the element lengths . 12 Step11. Delete un-needed entities from Nastran model. 13 Step12. Change Units. 14
Makefiles can be much more complicated than those outlined here,but for our needs in this tutorial these commands should suffice. Foradditional information on the make system, see the PDF manuallisted below.
Barhoum, Suliman Abdallah and Castillo, Rolando and Yethiraj, Anand (2012)Characterization of dynamics and internal structure of a mixed-surfactant wormlike micellar system using NMR and rheometry. Soft Matter, 8. pp. 6950-6957. ISSN 1744-6848
Varshney, Atul and Ghosh, Shankar and Bhattacharya, S. and Yethiraj, Anand (2012)Self organization of exotic oil-in-oil phases driven by tunable electrohydrodynamics. Scientific Reports, 2 (738). ISSN 2045-2322
Caines, Scott Clifford Peter (2012)Variation in the population dynamics of the invasive bryozoan Membranipora membranacea along a 450-km latitudinal gradient in Newfoundland and Labrador, Canada. Masters thesis, Memorial University of Newfoundland.
... absorption tests. (a) The analytical representation of the landing gear dynamic characteristics that is used... previous tests conducted on the same basic landing gear system that has similar energy absorption...
The annihilation of matter with antimatter represents the highest energy density of any known reaction, producing 10(exp 8) MJ/g, approximately 10 orders of magnitude more energy per unit mass than chemical based combustion. To take the first step towards using this energy for propulsion applications the NASA MSFC Propulsion Research Center (PRC) has initiated a research activity examining the storage of low energy antiprotons. Storage was identified as a key enabling technology since it builds the experience base necessary to understand the handling of antiprotons for virtually all utilization and high-density storage concepts. To address this need, a device referred to as the High Performance Antiproton Trap (HiPAT) is under development at the NASA MSFC PRC. The HiPAT is an electromagnetic system (Penning-Malmberg design) consisting of a 4 Tesla superconductor, a high voltage confinement electrode system (operation up to 20 KV), and an ultra high vacuum test section (operating in the 10(exp -12) torr range). The system was designed to be portable with an ultimate goal of maintaining 10(exp 12) charged particles with a half-life of 18 days. Currently, this system is being experimentally evaluated using normal matter ions which are cheap to produce and relatively easy to handle. These normal ions provide a good indication of overall trap behavior, with the exception of assessing annihilation losses. The ions are produced external to HiPAT using two hydrogen ion sources, with adjustable beam energy and current. Ion are transported in a beam line and controlled through the use of electrostatic optics. These optics serve to both focus and gate the incoming ions, providing microsecond-timed pulses that are dynamically captured by cycling the HiPAT electric containment field like a 'trap door'. The layout of this system more closely simulates the operations expected at an actual antiproton production facility where 'packets' of antiprotons with pulse widths measured in
Photoacoustic imaging is a molecular cum functional imaging modality based on differential optical absorption of the incident laser pulse by the endogeneous tissue chromophores. Several numerical simulations and finite element models have been developed in the past to describe and study Photoacoustic (PA) signal generation principles and study the effect of variation in PA parameters. Most of these simulation work concentrate on analyzing extracted 1D PA signals and each of them mostly describe only few of the building blocks of a Photoacoustic Tomography (PAT) imaging system. Papers describing simulation of the entire PAT system in one simulation platform, along with reconstruction is seemingly rare. This study attempts to describe how a commercially available Finite Element software (COMSOL(R)), can serve as a single platform for simulating PAT that couples the electromagnetic, thermodynamic and acoustic pressure physics involved in PA phenomena. Further, an array of detector elements placed at the boundary in the FE model can provide acoustic pressure data that can be exported to Matlab(R) to perform tomographic image reconstruction. The performance of two most commonly used image reconstruction techniques; namely, Filtered Backprojection (FBP) and Synthetic Aperture (SA) beamforming are compared. Results obtained showed that the lateral resolution obtained using FBP vs. SA largely depends on the aperture parameters. FBP reconstruction was able to provide a slightly better lateral resolution for smaller aperture while SA worked better for larger aperture. This interesting effect is currently being investigated further. Computationally FBP was faster, but it had artifacts along the spherical shell on which the data is projected.
To take the first step towards using the energy produced from the matter-antimatter annihilation for propulsion applications, the NASA Marshall Space Flight Center (MSFC) Propulsion Research Center (PRC) has initiated a research activity examining the storage of low energy antiprotons. The High Performance Antiproton Trap (HiPAT) is an electromagnetic system (Penning-Malmberg design) consisting of a 4 Tesla superconductor, a high voltage electrode confinement system, and an ultra high vacuum test section. It has been designed with an ultimate goal of maintaining 10(exp 12) charged particles with a half-life of 18 days. Currently, this system is being evaluated experimentally using normal matter ions that are cheap to produce, relatively easy to handle, and provide a good indication of overall trap behavior (with the exception of assessing annihilation losses). The ions are produced via a positive hydrogen ion source and transported to HiPAT in a beam line equipped with electrostatic optics. The optics serve to both focus and gate the incoming ions, providing microsecond-timed beam pulses that are dynamically captured by cycling the HiPAT forward containment field like a "trap door". Initial dynamic capture experiments have been successfully performed with beam energy and currents set to 1.9 kV and 23 micro-amps, respectively. At these settings up to 2x10(exp 9) ions have been trapped during a single dynamic cycle. 2ff7e9595c
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