Academic literature on the topic 'LS-PREPOST'

In this study, a computer program for calculating fatigue life of component is developed and introduced in LS-PrePost software. The program is written in Fortran programming language and the fatigue life equations used is taken from well-published literature. The materials covered are steel and aluminum. The developed program is able to read stress, strain and element values from d3plot and the keyword file. Having extracted the output from d3plot and keyword file, the fatigue life is then calculated and presented into a separate file called FATIGUE. The integration of output from FATIGUE will is displayed in LS-PrePost. Finally, the results of fatigue life contour are successfully displayed through LS-PrePost.

To study the fatigue damage of a cutter used for cutting cashew nut, the integrated<br />simulation platform is established with Hypermesh, LS-Dyna, LS-PrePost, and nCode GlyphWorks.<br />The simulation model is established by Hypermesh. LS-Dyna is used to calculate the k file.<br />LS-PrePost is used as the post-processing software. The rain-flow counting, load superposition and<br />extrapolation are executed using Rainflow module in nCode GlyphWorks. The analysis of the<br />fatigue damage of the cutter is executed using Stress Life module in nCode GlyphWorks. The<br />equivalent stress time history of different elements in the upper and lower cutters, rain-flow<br />counting histogram after load spectrum superposition, rain-flow counting histograms after load<br />spectrum extrapolation, and damage histogram of the cutter are obtained. The results show that the<br />cutter has excellent mechanical properties, and the minimum fatigue life of the cutter is about 495<br />days, which is a conservative solution.

The prototype testing of penetration requires a large amount of manpower, material and financial resources. So computer simulation technoolgy is used to save the resource.The process of high-speed penetration is simulated based on nonlinear dynamic analysis software ANSYS/LS-DYNA, and especially the simulation process of ANSYS/LS-DYNA is stated. Firstly, the theoretical analysis of material model and state equation are completed in the process of simulation. And by using the post-processor LS-PREPOST of LS-DYNA, the effective stress curve and acceleration changing curve were obtained. Simulation results show that: JOHNSON_COOK material model is correct in solving the problem of high-speed penetration, and the stress of internal projectile is decreasing along the axial direction.

In this paper, the universal nonlinear finite element software LS-DYNA is applied to the explicit dynamics simulation of shield’s soil cutting in tunneling, and using Non-reflective boundary of DYNA’s module, accurately conduct the dynamic analysis of shield’s tunneling. Finally Making visualization processing on the computed results with the post-processing soft LS-PREPOST. Compared with results of static’s simulation and small-sized shield experiment indoor, the explicit dynamics simulation used in the paper is in good agreement with them. Through the alleosis chat of internal energy, we can see that LS-DYNA can be commendably utilized to explicit dynamics simulation of soil cutting of shield’s cutter, simultaneously, we also concluded that moderately increasing the cutter opening rate will have a significant impact on improving the unearthed rate of soil residue, tunneling efficiency and lowering the total thrust force of the shield.

As a non-linear finite element analysis software ANSYS/LS-DYNA is used to carry out virtual reliability test in transmission mechanism of reciprocating compressor and response surface method is used to analyze reliability and sensitivity of sliding bearing according to testing data. This paper uses ANSYS to preprocess testing models of virtual prototype and put out the K file; designs sample points of random variables based on central composite method and modifies the K files to carry out random sampling of prototype and uses LS-DYNA970 to solve the submitted K files repeatedly; plots relationship curves of output responses and time history and gets a group of sample points of structure response with post-processing results of LS-PREPOST. Lastly this paper uses response surface method to build limit state equation and analyze reliability and sensitivity of sliding bearing, and provides theoretical basis for design of bearing.

It is significant for the phenomena of bouncing on water to analyze the ditching procedure of any kind of aircraft. The SPH method is employed to achieve a numerical simulation in the architecture of LS-DYNA and PrePost programs. The water domain is modeled by SPH and the boundary condition is discussed too. Through a set of contrastive analysis of different boundary conditions, some constructive suggestions of establishing the boundary conditions are given to deeply simulate aircraft ditching in the future.

The distribution of maximum equivalent stress on hemp stalks at different roller speeds were scavenged by LS-PREPOST function. The stress and strain distributions of hemp stalk under the transversely even-distributed load are analyzed through ANSYS software. The results show that hemp decortication largely depended on the rotation speed of separation roller and the feeding rate. In addition, the failure degree of bast fiber, the maturity and the water content of the stalk, and the difference in mechanical properties and geometrical size should be also taken into account.

Procedure of die design is mostly based on iterative try and error to obtain final design with good stamping formability. The stamping formability of sheet metal part is possible to be improved by adding addendum features at die model. In this paper discusses the effect of drawbars toward the formability of stamping process of aluminum AL6063. Effect of addendum size is evaluated Finite Element Simulation to prevent wrinkling and tearing. Simulation model is constructed by designing a simple die, punch and binder using variety drawbar diameters. The model further evaluated using LS-Dyna software interfaced by forming tool of LS-Prepost. Formability of the model is evaluated through yield stress, major strain and minor strain data. From the result of evaluation obtained that without draw beat, major/minor strain is above FLD while the formability is improved by applying 5 mm draw bead diameter.

The aim of this study is to investigate the effect of surface geometry for low-velocity impact applications. To achieve this purpose, aramid fiber-reinforced laminated polyester composite with various geometries such as cylindrical, elliptical, and spherical were prepared, and low-velocity impact properties were investigated numerically and experimentally. All properties such as orientation, fiber volume fraction, matrix material, and average thickness are the same in all samples. Experimental low-velocity impact behaviors of structure were determined by drop weight tester at low velocity 2.012 m/s. Simulations were carried out by LS-Prepost 4.2 and LS-Dyna v971 software. By this way, results of impact tests were verified and modeled with finite element method. Results of the impact tests showed that the elliptical samples have the highest energy absorption capability due to effective stress transfer capacity. According to experimental results, maximum energy absorption rate difference is 17% between elliptical 10 mm and cylindrical 5 mm geometries.

There are several techniques to simulate rebar reinforced concrete, such as smeared model, discrete model, embedded model, CLIS (constrained Lagrange in solid) model, and CBIS (constrained beam in solid) model. In this study, however, the interaction between the concrete elements and the reinforcement beam elements is only simulated by the discrete model and CBIS (constrained beam in solid) model. The efficiency and accuracy comparisons are investigated with reference to the analysis results by both models provided by LS-DYNA explicit finite element software. The geometric models are created using LS-PrePost, general purpose preprocessing software for meshing. The meshed models are imported to LS-DYNA where the input files are then analyzed. Winfrith and CSCM concrete material options are employed to describe the concrete damage behavior. The reinforcement material model is capable of isotropic and kinematic hardening plasticity. The load versus midspan deflection curves of the finite element models correlate with those of the experiment. Under the conditions of the same level of accuracy, the CBIS model is evaluated to have the following advantages over the discrete model. First, it has the advantage of reducing the time required for FE modeling; second, saving computer CPU time due to a reduction in total number of nodes; and third, securing a good aspect ratio of concrete elements.

The basis for performing a thermo-mechanical staggered coupled heat source analysis of a welding simulation is implemented into LS-DYNA. In this report, three methods for initiating the heat source’s mechanical motion during girth and tubular joint welding are developed and evaluated. The first method is a reformulation of the equations used at Det Norske Veritas, the second is an incorporation of the equations into excel and the third is a standalone third party software. The most efficient of the developed methods turned out to be the software which creates k-files which are implemented into the main k-file using LS-PrePost. All methods have been visually and numerically evaluated using Excel, LS-DYNA and LS-PrePost.

The idea to use finite element (FE) models to reconstruct accidents for humans is becoming more popular the last years. They represent the human body very accurately and indicate well changes in shape, size and biomechanical properties. FE models are useful when looking at complex factors in the human body in a more systematic way and when the approach is too complicated for conventional setups. Positioned child models from PIPER were used in the process and then rotated in LS-PrePost according to impact points and impact velocities from a given literature data where information from witnessed fall accidents of children was given. The simulations were finally run in LS-Dyna and the purpose was to investigate if the resulting brain injuries were similar to the real life data. From the literature, the falling distance from lowest point of the body to the ground, the age of the child, gender, type of ground and results from CT scans were all known. To compare the results to the literature data, section cuts of the brain were taken at four locations with different time steps. Biomechanical injury predictors such as brain strain, acceleration, rotational angular acceleration and rotational angular velocity were observed and helped with the comparison. In total, 12 cases were reconstructed which ended as 22 simulations. Due to uncertainty regarding the falling height when the children fell from a swing, each swing case had 3 scenarios. Overall the comparison of predicted injury locations from LS-Dyna to real injury locations from CT scans indicated that 7 out of 12 cases compared relatively well. The comparison of a 23-month-old girl to the same case reconsructed with CRABI-18 showed similar outcomes of the angular acceleration and the angular velocity. The linear acceleration and HIC were however much higher with LS-Dyna. Comparison between the swing cases of a 10-, 12- and 13-year-old resulted in similar results for the 12- and 13 year-old girls but the 10 year boy had lower values for all biomechanical parameters except the angular velocity which was a bit higher. With more detailed information about real accidents and precise scaling of PIPER child models, reconstruction with LS-Dyna could be useful in the future to design safer playgrounds for children and to obtain injury criterion for children after fall incidents.
Användande av finita element (FE) modeller för att rekonstruera olyckor har blivit allt populärare de senaste åren. De representerar människokroppen mycket noggrant och indikerar väl förändringari form, storlek och biomekaniska egenskaper. FE-modeller är användbara när man tittar på komplexa faktorer i människokroppen på ett mer systematiskt sätt och när tillvägagångssättet är för komplicerat för konventionella metoder. PIPER barnmodellerna positionerades i enlighet med islagpunkter och islaghastigheter från en given databas där informationen från vittnade fallolyckor av barn gavs. Simuleringarna kördes slutligen i LS-Dyna och syftet var att undersöka om predikteringarna liknade de resulterande hjärnskadorna. Från databasen var fallhöjd från kroppens lägsta punkt till marken, barnets ålder, kön, typ av mark och resultat från CT skanningar kända. För att jämföra resultaten med litteraturdata togs sektionsavsnitt av hjärnan på fyra platser med olika tidspunkter. Biomekaniska skadeprediktorer såsom hjärntöjning, acceleration, vinkelacceleration och vinkelhastighet extraherades och användes i jämförelsen. Totalt, rekonstruerades 12 fallolyckor med totalt 22 simuleringar. På grund av osäkerhet om fallhöjden när barnen föll från en gunga, hade varje fall från gunga 3 scenarier/fallhöjder var. Sammantaget indikerar jämförelsen av förväntade skadepredikteringar från LS-Dyna till observerade skador från CT-skanningar att 7 av 12 fall korrelerade relativt bra. Jämförelsen av en 23 månader gammal tjej i samma fall som tidigare också rekonstruerades med en CRABI-18 docka visade liknande resultat av vinkelaccelerationen och vinkelhastigheten. Linjär acceleration och HIC var emellertid mycket högre med LS-Dyna simuleringarna. Jämförelse mellan fallen från gunga hos en 10-, 12-och 13-åring resulterade i liknande resultat för 12- och 13-åriga flickor, medan 10-åringen hade lägre värden för alla biomekaniska parametrar utom den vinkelhastighet som var lite högre. Med mer detaljerad information om verkliga olyckor och exakt uppskalning av PIPER barnmodeller kan rekonstruktion med LS-Dyna vara användbar i framtiden för att utforma säkrare lekplatser för barn och för att få skadeskala för barn efter fallhändelser.

Diploma thesis is focused on the description of the parameters of nonlinear material models of concrete, which are implemented in a computational system LS-DYNA, interacting with performance of nonlinear test calculations in system LS-DYNA on selected problems, which are formed mainly by simulations of tests of mechanical and physical properties of concrete in uniaxial compressive and tensile on cylinders with applying different boundary conditions and by simulation of bending slab, with subsequent comparison of some results of test calculations with results of the experiment. The thesis includes creation of appropriate geometric models of selected problems, meshing of these geometric models, description of parameters and application of nonlinear material models of concrete on selected problems, application of loads and boundary conditions on selected problems and performance of nonlinear calculations in a computational system LS-DYNA. Evaluation of results is made on the basis of stress-strain diagrams and load-displacement diagrams based on nonlinear calculations taking into account strain rate effects and on the basis of hysteresis curves based on nonlinear calculations in case of application of cyclic loading on selected problems. Verification of nonlinear material models of concrete is made on the basis of comparison of some results of test calculations with results obtained from the experiment.