scholarly journals Finite element based acoustic analysis of dissipative silencers with high temperature and thermal-induced heterogeneity

2015 ◽  
Vol 101 ◽  
pp. 46-57 ◽  
Author(s):  
F.D. Denia ◽  
E.M. Sánchez-Orgaz ◽  
J. Martínez-Casas ◽  
R. Kirby
2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaoxiong Zha ◽  
Yang Zuo

This paper does some research on the mechanical property of multilayer container structure under high temperature and gives some suggestions on how to make fire protection based on the performance-based fire design. Firstly, using the software of FDS (Fire Dynamics Simulator), the fire background and fire heating release curve are determined. Through the simulation, the actual temperature curves (of the top and bottom temperature curves of the middle, door, and corner position in the container) are obtained and compared with the standard temperature curve of ISO-834. Secondly, using the software of Abaqus, a full scale finite element model of multilayer container structure is established. Two temperature fields under the standard temperature curve of ISO-834 and the actual temperature curve (of the most unfavorable curve of the top temperature curve of the middle position in the container) are obtained, respectively. Thirdly, the thermal-mechanical coupled analysis is carried out for the container structure under the wind loading and temperature field. The research result can be feasible in design and construction of container buildings and provides some references to corresponding specification preparation.


1999 ◽  
Vol 122 (1) ◽  
pp. 22-26 ◽  
Author(s):  
M. Law ◽  
W. Payten ◽  
K. Snowden

Modeling of welded joints under creep conditions with finite element analysis was undertaken using the theta projection method. The results were compared to modeling based on a simple Norton law. Theta projection data extends the accuracy and predictive capability of finite element modeling of critical structures operating at high temperature and pressure. In some cases analyzed, it was found that the results diverged from those gained using a Norton law creep model. [S0094-9930(00)00601-6]


2021 ◽  
Vol 903 ◽  
pp. 79-89
Author(s):  
R. Sundara Rao ◽  
K. Hemachandra Reddy ◽  
Ch.R. Vikram Kumar

In an internal combustion engine poppet valve is the crucial component which often opens and closes, thereby regulating gas flow in an engine cylinder. During engine operation, the valve is exposed to high temperature gases (thermal load) along with spring and cam loads (mechanical load). Due to high temperatures and fatigue loads, the valves are subjected to metallurgical changes and leads to failure. In order to resist these extreme conditions of high temperature and mechanical loads, the engine valve should possess special properties such as high surface hardness, a good amount of thermal conductivity, and fatigue strength. In this work, the reasons for the failure of two wheeler engine valve were evaluated and found that failure takes place due to change in the chemical composition mainly due to thermal diffusion at the interfaces. Thermal barrier coatings on the valve surface arrest the temperature load and increase its life. In this work, the performance of various titanium based composite coatings, i.e., TiN, TiC, TiC-Al2O3, TiCN, TiAlN, TiN- Al2O3, DLC, and uncoated valves of two wheeler engine was simulated using Finite Element Analysis. The simulation results indicated that coated valves have less thermal and fatigue loading and have more life than the uncoated valve. The Finite element simulation results of both coated and uncoated valves are presented and analyzed in this paper.


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.


Author(s):  
Brian Rose ◽  
James Widrig

High temperature piping systems and associated components, elbows and bellows in particular, are vulnerable to damage from creep. The creep behavior of the system is simulated using finite element analysis (FEA). Material behavior and damage is characterized using the MPC Omega law, which captures creep embrittlement. Elbow elements provide rapid yet accurate modeling of pinching of piping, which consumes a major portion of the creep life. The simulation is used to estimate the remaining life of the piping system, evaluate the adequacy of existing bellows and spring can supports and explore remediation options.


Author(s):  
Cristiana Delprete ◽  
Raffaella Sesana

The paper presents and discusses a low-cycle fatigue life prediction energy-based model. The model was applied to a commercial cast iron automotive exhaust manifold. The total expended energy until fracture proposed by the Skelton model was modified by means of two coefficients which take into account of the effects of mean stress and/or mean strain, and the presence of high temperature. The model was calibrated by means of experimental tests developed on Fe–2.4C–4.6Si–0.7Mo–1.2Cr high-temperature-resistant ductile cast iron. The thermostructural transient analysis was developed on a finite element model built to overtake confidentiality industrial restrictions. In addition to the commercial exhaust manifold, the finite element model considers the bolts, the gasket, and a cylinder head simulacrum to consider the corresponding thermal and mechanical boundary conditions. The life assessment performance of the energy-based model with respect the cast iron specimens was compared with the corresponding Basquin–Manson–Coffin and Skelton models. The model prediction fits the experimental data with a good agreement, which is comparable with both the literature models and it shows a better fitting at high temperature. The life estimations computed with respect the exhaust manifold finite element model were compared with different multiaxial literature life models and literature data to evaluate the life prediction capability of the proposed energy-based model.


2018 ◽  
Vol 30 ◽  
pp. 1-7 ◽  
Author(s):  
Fatih Hayati Çakır ◽  
Mehmet Alper Sofuoğlu ◽  
Selim Gürgen

Nickel-based alloys provide high corrosion resistance and high-temperature strength but these alloys possess poor machinability. Hastelloy-X is a nickel based alloy that has been used for high temperature use. There are many studies about finite element modeling of aerospace alloys but studies in literature with Hastelloy-X are limited. In the present work, machining characteristics of Hastelloy-X were investigated and a numerical model was developed for the turning operation of Hastelloy-X. Two input parameters (cutting speed and feed rate) were variated in the operations and the results were evaluated considering process outputs such as cutting forces, cutting temperature, effective stresses and chip morphology. Based on the verification of the numerical model using experimental results, presented material model is appropriate for the turning operation of Hastelloy-X at low and medium cutting speed machining conditions.


Designs ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 9
Author(s):  
Sujith Bobba ◽  
Shaik Abrar ◽  
Shaik Mujeebur Rehman

The present work deals with the development of a finite element methodology for obtaining the stress distributions in thick cylindrical HK40 stainless steel pipe that carries high-temperature fluids. The material properties and loading were assumed to be random variables. Thermal stresses that are generated along radial, axial, and tangential directions are generally computed using very complex analytical expressions. To circumvent such an issue, probability theory and mathematical statistics have been applied to many engineering problems, which allows determination of the safety both quantitatively and objectively based on the concepts of reliability. Monte Carlo simulation methodology is used to study the probabilistic characteristics of thermal stresses, and was implemented to estimate the probabilistic distributions of stresses against the variations arising due to material properties and load. A 2-D probabilistic finite element code was developed in MATLAB, and the deterministic solution was compared with ABAQUS solutions. The values of stresses obtained from the variation of elastic modulus were found to be low compared to the case where the load alone was varying. The probability of failure of the pipe structure was predicted against the variations in internal pressure and thermal gradient. These finite element framework developments are useful for the life estimation of piping structures in high-temperature applications and for the subsequent quantification of the uncertainties in loading and material properties.


Sign in / Sign up

Export Citation Format

Share Document