Nonlinear Finite-Element Analysis of Dual Support Breakaway Sign

Author(s):  
Gene W. Paulsen ◽  
John D. Reid

Breakaway supports are common devices used for dual support signs located along the roadway. Design of these systems often involves several costly vehicle crash tests to ensure their effectiveness. It is believed that mathematical modeling can be used to help develop new sign systems in a more timely and cost-effective manner. To this end, a dual support breakaway sign system was successfully modeled using LS-DYNA3D, a nonlinear, large deformation finite-element package. Small component models were first constructed on critical parts of the breakaway sign system. The component models were compared with physical component tests to aid in the development process, as well as to validate the results. The components were then assembled into a complete system model. Very few changes were made in the complete sign model, because problems were worked out in component modeling. Results from two full-scale vehicle crash tests were used to validate the system model. With successful results, the model can now be used to study various sign modifications and configurations.

Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.


Author(s):  
Rama Subba Reddy Gorla

Heat transfer from a nuclear fuel rod bumper support was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall heat transfer rates due to the thermodynamic random variables. These results can be used to identify quickly the most critical design variables in order to optimize the design and to make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in heat transfer and to the identification of both the most critical measurements and the parameters.


Author(s):  
Naveen Viswanatha ◽  
Mark Avis ◽  
Moji Moatamedi

The surround and the spider of the loudspeaker suspension are modelled in ANSYS to carry out finite element analysis. The displacement dependent nonlinearities arising from the suspension are studied and the material and geometric effects leading to the nonlinearities are parameterised. The ANSYS models are simulated to be excited by a sinusoidal load and the results are evaluated by comparison with the results obtained by a physical model. The paper illustrates how practical models can be analysed using cost effective finite element models and also the extension of the models to experiment on various parameters, like changing the geometry for optimisation, by computer simulation.


1993 ◽  
Vol 115 (3) ◽  
pp. 221-227
Author(s):  
A. K. Dhalla

Elevated temperature design has evolved over the last two decades from design-by-formula philosophy of the ASME Boiler and Pressure Vessel Code, Sections I and VIII (Division 1), to the design-by-analysis philosophy of Section III, Code Case N-47. The benefits of design-by-analysis procedures, which were developed under a US-DOE-sponsored high-temperature structural design (HTSD) program, are illustrated in the paper through five design examples taken from two U.S. liquid metal reactor (LMR) plants. Emphasis in the paper is placed upon the use of a detailed, nonlinear finite element analysis method to understand the structural response and to suggest design optimization so as to comply with Code Case N-47 criteria. A detailed analysis is cost-effective, if selectively used, to qualify an LMR component for service when long-lead-time structural forgings, procured based upon simplified preliminary analysis, do not meet the design criteria, or the operational loads are increased after the components have been fabricated. In the future, the overall costs of a detailed analysis will be reduced even further with the availability of finite element software used on workstations or PCs.


2021 ◽  
Author(s):  
Sinan Yıldırım ◽  
Ufuk Çoban ◽  
Mehmet Çevik

Suspension linkages are one of the fundamental structural elements in each vehicle since they connect the wheel carriers i.e. axles to the body of the vehicle. Moreover, the characteristics of suspension linkages within a suspension system can directly affect driving safety, comfort and economics. Beyond these, all these design criteria are bounded to the package space of the vehicle. In last decades, suspension linkages have been focused on in terms of design development and cost reduction. In this study, a control arm of a diesel public bus was taken into account in order to get the most cost-effective design while improving the strength within specified boundary conditions. Due to the change of the supplier, the control arm of a rigid axle was redesigned to find an economical and more durable solution. The new design was analyzed first by the finite element analysis software Ansys and the finite element model of the control arm was validated by physical tensile tests. The outputs of the study demonstrate that the new design geometry reduces the maximum Von Mises stress 15% while being within the elastic region of the material in use and having found an economical solution in terms of supplier’s criteria.


Author(s):  
Malcolm H. Ray

A method of comparing two acceleration time histories to determine whether they describe similar physical events is described. The method can be used to assess the repeatability of full-scale crash tests and it can also be used as a criterion for assessing how well a finite-element analysis of a collision event simulates a corresponding full-scale crash test. The method is used to compare a series of six identical crash tests and then is used to compare several finite-element analyses with full-scale crash test results.


Author(s):  
Nic Debusschere ◽  
Matthieu De Beule ◽  
Peter Dubruel ◽  
Patrick Segers ◽  
Benedict Verhegghe

Biodegradable stents, which temporarily support a stenotic blood vessel and afterwards fully disappear, have recently gained a lot of interest. They avoid long-term complications associated with conventional stents such as late stent thrombosis and in-stent restenosis. Moreover, degradable stents allow for a restoration of vasomotion and vessel growth which makes them particularly suitable for pediatric applications [1]. Finite element simulations have proven to be an efficient and cost-effective tool to investigate and optimize the mechanical performance of minimal invasive devices such as stents [2]. Biodegradable stents have however created new challenges in their design and optimization via finite element analysis because of their complex time-varying material behavior. To correctly simulate the mechanical behavior of biodegradable stents, a model should be developed that incorporates the effect of degradation upon all material characteristics. By combining existing constitutive material models based on continuum damage theory we were able to create such a virtual environment in which the transitional mechanical behavior of biodegradable stents can be investigated.


2014 ◽  
Vol 933 ◽  
pp. 603-607
Author(s):  
Ding Yue Chen ◽  
Li Hao Chen ◽  
Feng Lin ◽  
Dong Xu ◽  
An Chang

This paper is concerned with an optimization design for the solar car body under a single load is carried out by using finite element optimization design (FEOD) model. Topology optimization and sizing optimization are explored to find out an optimal manufacturing feasible design from multiple optimized designs of material reinforcement of the solar car body for rigidity improvement. The application of these methods demonstrates that through innovative utilization of the topology optimization technique, an optimal manufacturing feasible design can be obtained. The relationship between the rigidity improvement and different configuration of material reinforcement is also investigated. It is concluded that through appropriate application of FEOD methods, the overall rigidity of the solar car body framework can be improved substantially in a cost effective manner and provides more convincing evidence for optimization design of the solar car body. The results demonstrate that the optimized solar car body is safer and lighter.


Author(s):  
Facheng Wang ◽  
Zhigang Liu ◽  
Xinshuai Liu

Developments of oil and gas reservoirs in South China Sea are presently accelerated, to cope with the significant increase in energy demand from the mainland. Pipe-in-Pipe (PIP) flowline systems have been widely employed in this region and are continuously being considered for further developments. This is due to its significant thermal insulation capacity to deal with the High Pressure and High Temperature (HPHT) issue. However, the methods in industry for design of PIP systems usually have two side extremes. Simplified analytical approach may lack of accuracy and detailed FE analysis always brings considerably sophisticated modelling and post-processing tasks. To overcome this situation, COTEC Offshore Solutions, together with its mother company, China Offshore Oil Engineering Company, have developed a cost-effective, beam elements based, 3D simulation model using ABAQUS, a general purpose finite element analysis (FEA) package. The mode allows complicated structures of PIP system to be represented in an effective way and adopts a representation of stinger for S-lay installation analysis. A full-history time-dominate analysis from installation to operation is performed in one model, rather than the commonly used ‘snapshot’ analysis. In this study, a simplified modeling guidance of PIP components have been suggested. On the basis of the guidance, a novel 3D beam-elements based model has been produced to accurately represent complex PIP structural behaviors, but with minimum increase in modeling complexity. The analysis is carried out on the time-domain basis, which permits the full strain and stress history of the installation and operation to be observed and the most onerous time-point during the full installation and operation to be captured.


10.6036/9802 ◽  
2021 ◽  
Vol 96 (3) ◽  
pp. 242-245
Author(s):  
DAVID GARCÍA MENÉNDEZ ◽  
CARLOS LUMBRERAS IGLESIAS ◽  
MARIO ALONSO MENÉNDEZ ◽  
ROBERTO SUAREZ SIERRA

Electrical resistors for power lines are used worldwide as Neutral Earthing Resistors for short-circuit current reduction in power grids, and also as Filtering Resistors in combination with capacitors and inductances. The manufacturers of such resistors must certificate that they withstand the mechanical and thermal stresses imposed by the external loads, in accordance with IEC 62001 standard. Although this certification can be achieved by means of testing the resistor under working conditions, this process is both expensive and time-consuming. In this paper it is proposed a methodology for simulating the thermal and mechanical behavior of an electrical resistor, based on Multiphysics Finite Element Analysis. The methodology has been applied for the analysis of a filtering resistor for the Ethiopia-Kenia Power Systems Interconnection. Keywords: Earthing and Filtering Resistor, Multiphysics Finite Element Analysis, IEC 62001 short-circuit behavior.


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