Numerical Investigation of Hollow Metal Cross Section Profiles on Impact

2011 ◽  
Vol 383-390 ◽  
pp. 3241-3248 ◽  
Author(s):  
Waluyo Adi Siswanto ◽  
Badrul Omar ◽  
Shamsir Shukri
Keyword(s):  
Open Source ◽  
Numerical Investigation ◽  
Cross Section ◽  
Cross Sections ◽  
Open Source Software ◽  
Rigid Wall ◽  
Axial Mode ◽  
Hexagonal Shape ◽  
Vehicle Structure ◽  
Hollow Metal

A front bumper of a car is attached to the main vehicle structure by using hollow metals. This paper investigates various cross section profiles that can be used as bumper attachments. Several cross section profiles with the same circumscribe are firstly selected, i.e. round, square, triangular and hexagonal shape cross sections. Each model is then numerically impacted in an axial mode as if it is crashed into a rigid wall with an impacting velocity of 10 m/s or equivalent to 36 m/s. A dynamic-explicit open source software Impact is employed to do the simulation. The displacement results are monitored in the first 1:8ms then compared to the models that can absorb better showing the less displaced in certain examination nodes. The results shows that the triangle cross section performs better compared to other cross sections.

Collapse study of thin-walled polygonal section columns subjected to oblique loads

2007 ◽  
Vol 221 (7) ◽  
pp. 801-810 ◽  
Author(s):  
P Hosseini-Tehrani ◽  
S Pirmohammad
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Rigid Wall ◽  
Point Of View ◽  
Explicit Finite Element ◽  
Thin Walled ◽  
Oblique Load ◽  
Crash Behaviour ◽  
Vehicle Crashworthiness ◽  
Load Conditions

The present paper deals with the collapse simulation of aluminium alloy extruded polygonal section columns subjected to oblique loads. Oblique load conditions in numerical simulations are applied by means of impacting a declined rigid wall on the tubes with no friction in this task. The explicit finite element code LS-DYNA is used to simulate the crash behaviour of polygonal section columns that are undergoing both axial and bending collapse situations. In order to validate LS-DYNA results the collapse procedure of square columns is successfully simulated and the obtained numerical results are compared with actual available experimental data. Mean crush loads and permanent displacements corresponding to load angles have been investigated, considering columns with square, hexagonal, octagonal, decagonal, and circular cross-sections. It is shown that the octagonal cross-section has better characteristics from the point of view of vehicle crashworthiness under oblique load conditions.

Fire resistance of DELTABEAM® composite beams: a numerical investigation

2017 ◽  
Vol 8 (4) ◽  
pp. 338-353 ◽  
Author(s):  
Chrysanthos Maraveas
Keyword(s):  
Numerical Investigation ◽  
Cross Section ◽  
Cross Sections ◽  
Fire Resistance ◽  
Elevated Temperatures ◽  
Ambient Conditions ◽  
Content Type ◽  
Technical Manual ◽  
Manufacturing Company ◽  
Parametric Analyses

Purpose The DELTA® beam composite floor system is a recently developed shallow floor type that has seen many applications in contemporary construction. It involves partially encasing DELTA® steel beams in concrete, with the lower flange remaining exposed. Besides the satisfactory behavior of the system at ambient conditions, understanding its response under elevated temperatures is critical in evaluating its overall performance. Despite certification from the manufacturing company that the system has adequate fire resistance, its behavior under fire conditions has neither been investigated to depth nor reported in detail. The purpose of this paper is the detailed numerical investigation of their behavior in fire. For this reason, the finite element method was implemented in this paper to simulate the response of such beams subjected to fire. Material properties were modeled according to the Eurocodes. The coupled thermal-structural parametric analyses involved four different variations of the “shortest” and “deepest” cross-section (eight case studies in total) specified by the manufacturing company. Other simulations of these cross-sections, in which either the thermal expansion or the structural load were not taken into account, were carried out for comparison purposes. Design/methodology/approach The methodology for simulating such systems, which has been successfully implemented and validated against fire test results elsewhere (Maraveas et al., 2012) was also followed here. To investigate the statement made by Maraveas et al. (2014) and the equations proposed by Zaharia and Franssen (2012) that the insulation is not so effective for “short” cross-sections, two beams, one with a D20-200 (Deltabeam Technical Manual, 2013) cross-section (shallowest section) and one with a D50-600 (Deltabeam Technical Manual, 2013) cross-section (deepest section), were simulated in this paper for comparison purposes. Additionally, reasonable assumptions were made for the cross-sectional dimensions not specified by the manufacturer (Deltabeam Technical Manual, 2013) and parametric analyses were carried out to investigate their effect on the structural response of the system. Findings Composite DELTA® beams can achieve fire resistances ranging from 120 to 180 min, depending on the depth and geometry of their cross-section, with deeper sections displaying a better fire response. The intense thermal bowing that occurs when these beams are heated from below has a more pronounced effect, in terms of thermally induced deflections for deeper sections. The satisfactory fire resistance of these beams is achieved due to the action of the concrete encased web and the reinforcement which compensate for the loss of the exposed lower flange. Increasing the thickness of the web in deeper sections improves their fire rating up to 180 min. The thickness of the lower flange affects the fire rating of the beams only in a minor way. Practical/implications The paper describes a numerical methodology to estimate the fire resistance of complex flooring systems.

Numerical Investigation and Optimization of Shape and Design Parameters of Lift Rod of Helicopter

2019 ◽  
Vol 11 (3) ◽  
Author(s):  
R. Saravanan ◽  
T. Gopalakrishnan
Keyword(s):  
Numerical Investigation ◽  
Failure Mode ◽  
Cross Section ◽  
Cross Sections ◽  
Mode Analysis ◽  
Design Parameters ◽  
Force System ◽  
Good Design ◽  
Failure Mode Analysis ◽  
Functional Components

The technological advantages lead to design the components and systems of great extent. The functional components and their dimensions are to be designed well for ensuring safe and reliable operations. The lift rod of helicopter is considered here for optimization. The failure mode analysis results show that the lift rod fails often and found to have less life period because of some complex force system that is encountered while landing, take-off and continuation of flight. Initially the existing design parameters and cross sections were considered as it is for observation. Based on the observation, the cross section was optimized to some extent. Then the design parameters are increased to 3 levels. The lift rod is analysed again with modified parameters. Finally, both the dimensions and shape are optimized to achieve a good design with desirable characteristics.

Experimental and Numerical Investigation of the DrivAer Model

2012 ◽  
Author(s):  
Angelina I. Heft ◽  
Thomas Indinger ◽  
Nikolaus A. Adams
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Open Source ◽  
Numerical Investigation ◽  
Open Source Software ◽  
The Other ◽  
Interference Effects ◽  
Aerodynamic Optimization ◽  
Car Model ◽  
High Degree

Automotive aerodynamic research often focuses on strongly simplified car models, such as the Ahmed body and the SAE model. Due to their high degree of abstraction, however, interference effects are often neglected which leads to an unrealistic representation of the flow field. Consequently, these results cannot be directly used for the aerodynamic optimization of production vehicles. On the other hand, aerodynamic investigations of real production vehicles are often limited due to the restricted availability of the geometric data. Therefore, a new realistic generic car model for aerodynamic research — the DrivAer body — is proposed. This paper focuses on the development of the model, summarizes first experimental results of the different configurations of the fastback geometry and compares them to numerical simulations performed using the open source software OpenFOAM®.

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Oxygen K near edge structures studied with multiple scattering calculations

1988 ◽  
Vol 46 ◽  
pp. 504-505
Author(s):  
Xudong Weng ◽  
Peter Rez
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Partial Cross Section ◽  
Energy Window ◽  
Edge Structure ◽  
Fine Structures ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

Absolute inner-shell cross section determination for EELS analysis

1988 ◽  
Vol 46 ◽  
pp. 534-535
Author(s):  
P.A. Crozier
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absolute Cross Section ◽  
Specimen Thickness ◽  
Mass Thickness ◽  
Scattering Cross ◽  
Before And After ◽  
Estimated Error ◽  
Scattering Cross Sections ◽  
Electron Microscopist

Absolute inelastic scattering cross sections or mean free paths are often used in EELS analysis for determining elemental concentrations and specimen thickness. In most instances, theoretical values must be used because there have been few attempts to determine experimental scattering cross sections from solids under the conditions of interest to electron microscopist. In addition to providing data for spectral quantitation, absolute cross section measurements yields useful information on many of the approximations which are frequently involved in EELS analysis procedures. In this paper, experimental cross sections are presented for some inner-shell edges of Al, Cu, Ag and Au.Uniform thin films of the previously mentioned materials were prepared by vacuum evaporation onto microscope cover slips. The cover slips were weighed before and after evaporation to determine the mass thickness of the films. The estimated error in this method of determining mass thickness was ±7 x 107g/cm2. The films were floated off in water and mounted on Cu grids.

A technique for preparing semiconductor cross sections for both TEM and SEM analysis

1989 ◽  
Vol 47 ◽  
pp. 712-713
Author(s):  
Stanley J. Klepeis ◽  
J.P. Benedict ◽  
R.M Anderson
Keyword(s):  
Sample Preparation ◽  
Cross Section ◽  
Cross Sections ◽  
Sem Analysis ◽  
Preparation Technique ◽  
Ion Milling ◽  
Tem Analysis ◽  
Polished Cross Section ◽  
Area Of Interest ◽  
Polished Side

The ability to prepare a cross-section of a specific semiconductor structure for both SEM and TEM analysis is vital in characterizing the smaller, more complex devices that are now being designed and manufactured. In the past, a unique sample was prepared for either SEM or TEM analysis of a structure. In choosing to do SEM, valuable and unique information was lost to TEM analysis. An alternative, the SEM examination of thinned TEM samples, was frequently made difficult by topographical artifacts introduced by mechanical polishing and lengthy ion-milling. Thus, the need to produce a TEM sample from a unique,cross-sectioned SEM sample has produced this sample preparation technique.The technique is divided into an SEM and a TEM sample preparation phase. The first four steps in the SEM phase: bulk reduction, cleaning, gluing and trimming produces a reinforced sample with the area of interest in the center of the sample. This sample is then mounted on a special SEM stud. The stud is inserted into an L-shaped holder and this holder is attached to the Klepeis polisher (see figs. 1 and 2). An SEM cross-section of the sample is then prepared by mechanically polishing the sample to the area of interest using the Klepeis polisher. The polished cross-section is cleaned and the SEM stud with the attached sample, is removed from the L-shaped holder. The stud is then inserted into the ion-miller and the sample is briefly milled (less than 2 minutes) on the polished side. The sample on the stud may then be carbon coated and placed in the SEM for analysis.

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