Numerical Simulation of Thermal Stress for a Liquid-Cooled Exhaust Manifold

2008 ◽  
Author(s):  
Dong Fu ◽  
Dui Huang ◽  
Ahmed Juma ◽  
Curtis M. Schreiber ◽  
Xiuling Wang ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Large Temperature ◽  
Space Partitioning ◽  
Experiment Data ◽  
Industrial Experiment ◽  
Binary Space Partitioning ◽  
Current Design ◽  
Computational Fluid Dynamics Cfd

Liquid-cooled exhaust manifolds are widely used in turbocharged diesel engines. The large temperature gradient in the overall manifold will cause remarkable thermal stress. The objective of the project is to modify the current design for preventing the high thermal stress and extending the life span of the manifold. To achieve the objective, the combination between Computational Fluid Dynamics (CFD) with Finite Element (FE) is introduced. Firstly, CFD analysis is conducted to obtain temperature distribution, providing boundary conditions of the thermal load on the FE mesh. Afterward, FE analysis is carried out to determine the thermal stress. The interpolation of the temperature data from CFD to FE is done by Binary Space Partitioning (BSP) tree algorithm. To accurately quantify the thermal stress, nonlinear material behavior is considered. The computational results are compared with that of Number of Transfer Units (NTU) method, and are further verified with industrial experiment data. All these comparisons indicate that present investigation reasonably predicts the thermal stress behavior. Based on the results, recommendations are given to optimize the manifold design.

Numerical Simulation of Thermal Stress for a Liquid-Cooled Exhaust Manifold

2009 ◽  
Vol 1 (3) ◽  
Author(s):  
Dong Fu ◽  
Dui Huang ◽  
Ahmed Juma ◽  
Curtis M. Schreiber ◽  
Xiuling Wang ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Large Temperature ◽  
Space Partitioning ◽  
Experiment Data ◽  
Operation Condition ◽  
Binary Space Partitioning ◽  
Current Design ◽  
Computational Fluid Dynamics Cfd

Liquid-cooled exhaust manifolds are widely used in turbocharged diesel engines. The large temperature gradient in the overall manifold can cause remarkable thermal stress. The objective of the project is to optimize the operation condition and modify the current design in order to prevent high thermal stress and to extend the lifespan of the manifold. To achieve the objective, the combination between computational fluid dynamics (CFD) with finite element (FE) is introduced. First, CFD analysis is conducted to obtain temperature distribution, providing conditions of the thermomechanical loading on the FE mesh. Next, FE analysis is carried out to determine the thermal stress. The interpolation of the temperature data from CFD to FE is done by binary space partitioning tree algorithm. To accurately quantify the thermal stress, nonlinear material behavior is considered. Based on stresses and strains, the fatigue life can be estimated. The CFD results are compared with that of the number of transfer units’ method and are further verified with industrial experiment data. All these comparisons indicate that the present investigation reasonably predicts the thermal stress behavior. Based on the results, recommendations are given to optimize the manifold design and operation.

Structural Response and Remaining Life of Damaged Composites

2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman
Keyword(s):  
Hybrid Approach ◽  
Experimental Studies ◽  
Structural Response ◽  
Material Behavior ◽  
Experimental Results ◽  
Life Assessment ◽  
Nonlinear Material ◽  
Remaining Life ◽  
Design Effectiveness ◽  
Remaining Life Assessment

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.

Analysis of Thermal Stresses and Residual Stress Changes in Railroad Wheels Caused by Severe Drag Braking

1977 ◽  
Vol 99 (1) ◽  
pp. 18-23 ◽  
Author(s):  
M. R. Johnson ◽  
R. E. Welch ◽  
K. S. Yeung
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Yield Point ◽  
Thermal Stresses ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Residual Stress Field ◽  
Thermal Stress Field ◽  
Stress Changes ◽  
Railroad Wheels

A finite-element computer program, which takes into consideration nonlinear material behavior after the yield point has been exceeded, has been used to analyze the thermal stresses in railroad freight car wheels subjected to severe drag brake heating. The analysis has been used with typical wheel material properties and wheel configurations to determine the thermal stress field and the extent of regions in the wheel where the yield point is exceeded. The resulting changes in the residual stress field after the wheel has cooled to ambient temperature have also been calculated. It is shown that severe drag braking can lead to the development of residual circumferential tensile stresses in the rim and radial compressive stresses in the plate near both the hub and rim fillets.

Response surface method strategies coupled with NLFEA for structural reliability analysis of prestressed bridges

2021 ◽  
Author(s):  
Silvia J. Sarmiento Nova ◽  
Jaime Gonzalez-Libreros ◽  
Gabriel Sas ◽  
Rafael A. Sanabria Díaz ◽  
Maria C. A. Texeira da Silva ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Response Surface ◽  
Response Surface Method ◽  
Structural Reliability ◽  
Limit State ◽  
Material Behavior ◽  
Nonlinear Material ◽  
State Function ◽  
Surface Method ◽  
Highly Nonlinear

<p>The Response Surface Method (RSM) has become an essential tool to solve structural reliability problems due to its accuracy, efficacy, and facility for coupling with Nonlinear Finite Element Analysis (NLFEA). In this paper, some strategies to improve the RSM efficacy without compromising its accuracy are tested. Initially, each strategy is implemented to assess the safety level of a highly nonlinear explicit limit state function. The strategy with the best results is then identified and used to carry out a reliability analysis of a prestressed concrete bridge, considering the nonlinear material behavior through NLFEA simulation. The calculated value of &#120573; is compared with the target value established in Eurocode for ULS. The results showed how RSM can be a practical methodology and how the improvements presented can reduce the computational cost of a traditional RSM giving a good alternative to simulation methods such as Monte Carlo.</p>

scholarly journals Multispecies Coevolution Particle Swarm Optimization Based on Previous Search History

2017 ◽  
Vol 2017 ◽  
pp. 1-22
Author(s):  
Danping Wang ◽  
Kunyuan Hu ◽  
Lianbo Ma ◽  
Maowei He ◽  
Hanning Chen
Keyword(s):  
Particle Swarm Optimization ◽  
Statistical Tests ◽  
Particle Swarm ◽  
Local Optimum ◽  
Space Partitioning ◽  
Swarm Optimization ◽  
Real World Problem ◽  
Binary Space Partitioning ◽  
Solution Accuracy ◽  
Search History

A hybrid coevolution particle swarm optimization algorithm with dynamic multispecies strategy based on K-means clustering and nonrevisit strategy based on Binary Space Partitioning fitness tree (called MCPSO-PSH) is proposed. Previous search history memorized into the Binary Space Partitioning fitness tree can effectively restrain the individuals’ revisit phenomenon. The whole population is partitioned into several subspecies and cooperative coevolution is realized by an information communication mechanism between subspecies, which can enhance the global search ability of particles and avoid premature convergence to local optimum. To demonstrate the power of the method, comparisons between the proposed algorithm and state-of-the-art algorithms are grouped into two categories: 10 basic benchmark functions (10-dimensional and 30-dimensional), 10 CEC2005 benchmark functions (30-dimensional), and a real-world problem (multilevel image segmentation problems). Experimental results show that MCPSO-PSH displays a competitive performance compared to the other swarm-based or evolutionary algorithms in terms of solution accuracy and statistical tests.

scholarly journals Finite Element Software for Rubber Products Design

2018 ◽  
Vol 3 (1) ◽  
pp. 13-20
Author(s):  
Dávid Huri
Keyword(s):  
Finite Element ◽  
Complex Analysis ◽  
Large Deformations ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Material Models ◽  
Finite Element Software ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Different Types

Automotive rubber products are subjected to large deformations during working conditions, they often contact with other parts and they show highly nonlinear material behavior. Using finite element software for complex analysis of rubber parts can be a good way, although it has to contain special modules. Different types of rubber materials require the curve fitting possibility and the wide range choice of the material models. It is also important to be able to describe the viscoelastic property and the hysteresis. The remeshing possibility can be a useful tool for large deformation and the working circumstances require the contact and self contact ability as well. This article compares some types of the finite element software available on the market based on the above mentioned features.

scholarly journals Meshless Radial Point Interpolation Method for Hyperelastic Materials

10.29007/r7sp ◽  
2020 ◽  
Author(s):  
Trong Khiem Bui ◽  
Vu Tuong Nguyen ◽  
Thanh Nha Nguyen ◽  
Tich Thien Truong
Keyword(s):  
Large Deformation ◽  
Interpolation Method ◽  
Biological Tissues ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Radial Point Interpolation Method ◽  
Hyperelastic Materials ◽  
Radial Point Interpolation ◽  
Point Interpolation Method ◽  
Point Interpolation

Hyperelastic materials are special types of material that tends to behavior elastically when they are subjected to very large strains. These materials show not only the nonlinear material behavior but also the large deformation and stress-strain relationship is derived from a strain energy density function. Hyperelastic materials are widely used in many applications such as biological tissues, polymeric foams, and moreover. Neo - Hookean is a material model for hyperelastic solid which contains only two material parameters: bulk modulus and shear modulus. In the field of numerical analysis, the radial point interpolation method (RPIM) is a well-known meshfree method based on Garlekin's weak form. With the property of “free of mesh”, the RPIM approach shows its advantage for large deformation problems. In this study, a meshless radial point interpolation method is applied to demonstrate the elastic response of rubber-like materials based on the Mooney- Rivlin model. The obtained results are compared with the reference solutions given by other methods to verify the accuracy of the proposed method.

Numerical Estimation of Flow Penetrating Depth Into Stagnant Branch Pipes for Thermal Fatigue Prediction

2014 ◽  
Author(s):  
Yoshihiro Ishikawa ◽  
Yukihiko Okuda ◽  
Naoto Kasahara
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Temperature Fluctuation ◽  
Thermal Stratification ◽  
Branch Pipe ◽  
Large Temperature ◽  
Bend Pipe ◽  
Main Pipe ◽  
High Temperature Water ◽  
Temperature Water

In the nuclear power plants, there are many branch pipes with closed-end which are attached vertically to the main pipe. We consider a situation in which the high temperature water is transported in the main pipe, the branch pipe is filled with stagnant water which has lower temperature than the main flow, and the end of the branch pipe is closed. At the branch connection part, it is known that a cavity flow is induced by the shear force of the boundary layer which separates from the leading edge of the branch pipe along the main pipe wall. In cases where the high temperature water penetrates into the branch pipe, there is a possibility that a steep and large temperature gradient field, called “thermal stratification layer” is formed at the boundary between high and low temperature water in the branch pipe. If the thermal stratification layer is formed in a bend pipe, which is used for connecting the vertical branch pipe and to a horizontal pipe, at the same time, the temperature fluctuation by the thermal stratification layer motion occurs, there may cause the thermal stress in the piping material. Furthermore, keeping the piping material under the thermal stress, there might be a possibility of a crack on the surface of the bend pipe. For this reason, the evaluation of the position where the thermal stratification layer reaches is very important during early piping design process. And, deeply understanding regarding the phenomena, is also important. However, because of the complexities of the phenomena, it is difficult to immediately clarify the whole mechanisms of the thermal stress arising due to the temperature fluctuation by the thermal stratification layer change. The complete prediction method for the position of the thermal stratification layer based on the mechanisms that is able to be applied to any piping system, any temperature and any velocity conditions, is also difficult. Therefore, a practical approach is required. The authors attempt to develop the practical estimation method for the thermal stratification layer position using the three-dimensional Navier-Stokes simulation which was based on the Reynolds-average in order to reduce the computational costs. In this paper, three different configurations of the piping were simulated and the simulation results were compared with the experimental results obtained by the other research group.

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