Robust Design Approach to 2 Inch and 3 Inch Thermal Tees on 14 Inch Pipework for Hot and Cold Fluid Turbulent Mixing at the Branch-Run Interface

2020 ◽  
Author(s):  
Phil Wallace
Keyword(s):  
Robust Design ◽  
Thermal Fatigue ◽  
Turbulent Mixing ◽  
High Stress ◽  
Internal Diameter ◽  
Geometric Features ◽  
Concept Design ◽  
Design Life ◽  
Cold Fluid ◽  
Computational Fluid Dynamics Analysis

Abstract This paper presents a concept design methodology to establish robust designs against thermal fatigue of 2″ and 3″ thermal tee branch sizes on 14″ pipework, which are subjected to relatively hot and cold fluid turbulent mixing, for use in Pressurised Water Reactor Plant. Thermal tees can be subjected to extremely demanding thermal fatigue conditions, e.g. high temperature fluctuations causing high stress ranges where hot and cold fluid mix at the tee position from different branches of the system, these conditions ultimately limiting design life. Prior to conducting a full design justification to the ASME Section III code [1], which for these components Rolls-Royce has justified by a section NB3200 approach using finite element analysis and computational fluid dynamics, analysis/iteration time can be saved, and the likelihood of a robust design being found increased, by understanding the effect and significance of geometric features of the tees. Fundamentally, establishing which features have a greater influence on the thermal fatigue performance of the tee and setting maximum and minimum values for these features. This paper presents an approach that can be used in the concept design phase to understand the influence of variables such as: branch throat internal diameter, run versus branch reinforcement, inclusion of integral orifices and branch fluid flow rate, and also of how they interact with each other in relation to providing a code compliant design. The approach is also used to size such features so that they are away from ‘cliff edges’ in performance, i.e. away from values that are likely to produce high stress levels and reduce design life. The paper covers: the variables chosen to be investigated, the methodology including the associated stress models to understand the effect of variable change and positioning in the ‘design landscape’, and identifies which geometric features should be maximised or minimised in size to maximise thermal fatigue life.

scholarly journals SIMULTANEOUS DEFINITION OF KEY CHARACTERISTICS IN ORDER TO FACILITATE ROBUST DESIGN IN EARLY PRODUCT DEVELOPMENT STAGES

2021 ◽  
Vol 1 ◽  
pp. 2691-2700
Author(s):  
Stefan Goetz ◽  
Dennis Horber ◽  
Benjamin Schleich ◽  
Sandro Wartzack
Keyword(s):  
Product Development ◽  
Robust Design ◽  
Language Processing ◽  
Design Stage ◽  
Concept Design ◽  
Clear Definition ◽  
Implicit Information ◽  
Key Characteristics ◽  
Associated Functions ◽  
Definition Of

AbstractThe success of complex product development projects strongly depends on the clear definition of target factors that allow a reliable statement about the fulfilment of the product requirements. In the context of tolerancing and robust design, Key Characteristics (KCs) have been established for this purpose and form the basis for all downstream activities. In order to integrate the activities related to the KC definition into product development as early as possible, the often vaguely formulated requirements must be translated into quantifiable KCs. However, this is primarily a manual process, so the results strongly depend on the experience of the design engineer.In order to overcome this problem, a novel computer-aided approach is presented, which automatically derives associated functions and KCs already during the definition of product requirements. The approach uses natural language processing and formalized design knowledge to extract and provide implicit information from the requirements. This leads to a clear definition of the requirements and KCs and thus creates a founded basis for robustness evaluation at the beginning of the concept design stage. The approach is exemplarily applied to a window lifter.

Predicting Thermal Mixing and Fatigue Inside Control Rod Guide Tubes

2013 ◽  
Author(s):  
Eric Lillberg
Keyword(s):  
Thermal Fatigue ◽  
Turbulent Mixing ◽  
Low Frequency ◽  
Experimental Measurements ◽  
Guide Tube ◽  
Control Rod ◽  
Thermal Mixing ◽  
Purge Flow ◽  
Control Rods ◽  
Good Agreement

The cracked control rods shafts found in two Swedish NPPs were subjected to thermal fatigue due to mixing of cold purge flow with hot bypass water in the upper part of the top tube on which the control rod guide tubes rests. The interaction between the jets formed at the bypass water inlets is the main source of oscillation resulting in low frequency downward motion of hot bypass water into the cold purge flow. This ultimately causes thermal fatigue in the control rod shaft in the region below the four lower bypass water inlets. The transient analyses shown in this report were done to further investigate this oscillating phenomenon and compare to experimental measurements of water temperatures inside the control rod guide tube. The simulated results show good agreement with experimental data regarding all important variables for the estimation of thermal fatigue such as peak-to-peak temperature range, frequency of oscillation and duration of the temperature peaks. The results presented in this report show that CFD using LES methodology and the open source toolbox OpenFOAM is a viable tool for predicting complex turbulent mixing flows and thermal loads.

scholarly journals Early Robust Design—Its Effect on Parameter and Tolerance Optimization

2021 ◽  
Vol 11 (20) ◽  
pp. 9407
Author(s):  
Stefan Goetz ◽  
Martin Roth ◽  
Benjamin Schleich
Keyword(s):  
Product Development ◽  
Robust Design ◽  
Product Development Process ◽  
Design Parameters ◽  
Concept Design ◽  
Design Decisions ◽  
Dynamic Markets ◽  
Tolerance Optimization ◽  
Qualitative Approaches ◽  
Design Activities

The development of complex products with high quality in dynamic markets requires appropriate robust design and tolerancing workflows supporting the entire product development process. Despite the large number of methods and tools available for designers and tolerance engineers, there are hardly any consistent approaches that are applicable throughout all development stages. This is mainly due to the break between the primarily qualitative approaches for the concept stage and the quantitative parameter and tolerance design activities in subsequent stages. Motivated by this, this paper bridges the gap between these two different views by contrasting the used terminology and methods. Moreover, it studies the effects of early robust design decisions with a focus on Suh’s Axiomatic Design axioms on later parameter and tolerance optimization. Since most robust design activities in concept design can be ascribed to these axioms, this allows reliable statements about the specific benefits of early robust design decisions on the entire process considering variation in product development for the first time. The presented effects on the optimization of nominal design parameters and their tolerance values are shown by means of a case study based on ski bindings.

Evaluation on Stress Relaxation Properties of Geomembrane

2010 ◽  
Vol 168-170 ◽  
pp. 1572-1576
Author(s):  
Si Fa Xu ◽  
Yong Zhang ◽  
Zhe Wang
Keyword(s):  
Stress Relaxation ◽  
Tensile Force ◽  
High Stress ◽  
Elastic Model ◽  
Design Strength ◽  
Elapsed Time ◽  
Side Slope ◽  
Design Life ◽  
Liner System ◽  
Long Time

Geomembrane installed on the bottom and the side slope of a waste landfill as liner system is made of high density polyethylene or thermo plastic elastmer polyplopylene. Stress in the geotextile is caused by friction between the waste and the geotextile which is a result of the compression of the disposed waste, and the tensile force is transferred into the liner system by friction. With elapsed time, the stress relaxation will occur under certain strain conditions. If the stress of geomembrane is at high stress for a long period of time, the long time design strength of the geomembrane may be controlled by the creep at the end of the design life. So it is very important for design to determine the stress induced in the geomembrane. In this paper, the authors present a formula based three element visco-elastic model to evaluate the relation between the stress and elapsed time. Then the authors present some results of modeled tests conducted, it is shown that the relation between the material characteristic and temperature by indoor experiment.

Measurement of Red Cell Modulus of Elasticity by in-Vitro and Model Cell Experiments

1970 ◽  
Vol 92 (3) ◽  
pp. 604-609 ◽  
Author(s):  
T. W. Hoeber ◽  
R. M. Hochmuth
Keyword(s):  
Modulus Of Elasticity ◽  
Relaxation Times ◽  
High Stress ◽  
Red Cells ◽  
Stress And Strain ◽  
Internal Diameter ◽  
Membrane Stress ◽  
Membrane Elasticity ◽  
Model Cell

Because of the small size of the human red blood cell, it is difficult to measure the elasticity of the cell membrane. Previous techniques of measuring membrane elasticity involve high stress and strain and therefore do not adequately characterize the membrane’s elasticity near its equilibrium (biconcave) shape. In order to determine elasticity at low stress and strain, an experiment was designed to involve minimal membrane stress. In the experiment, the red cells are expelled from glass micropipettes on the order of 3 microns in internal diameter. The cell is in a folded deformed shape within the confines of the tip but once it leaves the pipette the cell returns to its biconcave shape. With the use of dimensional analysis, the characteristic relaxation times of the red cells and of geometrically similar, fluid-filled model cells are compared and a modulus of elasticity of approximately 106 dynes/cm2 is calculated.

Numerical Investigation of Turbulent Flow in a T-Junction

2011 ◽  
Author(s):  
Jungwoo Kim ◽  
Jae Jun Jeong
Keyword(s):  
Thermal Fatigue ◽  
Turbulent Mixing ◽  
Azimuthal Angle ◽  
Dominant Frequency ◽  
Frequency Characteristics ◽  
Turbulent Pipe Flow ◽  
Energy Spectra ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy

In the present study, a large eddy simulation, at conditions of experiments by Vattenfall, was performed in order to investigate the phenomenon of turbulent mixing affecting the thermal fatigue in a T-junction. Mean velocity and turbulence intensity from the simulation are compared against those measured in the Vattenfall experiment, and the observed agreement is good. Based on the numerical results from the LES, the energy spectra were examined because they have been regarded as being of primary importance in the study on the thermal fatigue according to previous studies. The energy spectra showed the dominant frequency of around St = 0.5 agrees with the value reported in experiments. Also, near the T-junction the frequency characteristics are shown to depend on the azimuthal angle. However, this dependency of the frequency characteristics on the azimuthal angle is disappeared in downstream because the turbulence in the T-junction eventually approaches the fully-developed turbulent pipe flow. On the other hand, although not shown here, the dominant frequency near the wall is different from that reported at the centerline (St∼1), meaning that the thermal fatigue may not result from the wake structure, and is affected by the vertical structures existing near the wall. This result is consistent with one stated by [1] that the frequency characteristics are closely associated with arched vortices.

scholarly journals Design of a robust stair-climbing compliant modular robot to tackle overhang on stairs

Robotica ◽  
2018 ◽  
Vol 37 (3) ◽  
pp. 428-444 ◽  
Author(s):  
Ajinkya Bhole ◽  
Sri Harsha Turlapati ◽  
Rajashekhar V.S ◽  
Jay Dixit ◽  
Suril V. Shah ◽  
...  
Keyword(s):  
Taguchi Method ◽  
Robust Design ◽  
Stair Climbing ◽  
Parameter Design ◽  
Design Parameters ◽  
Concept Design ◽  
Modular Robot ◽  
Optimal Setting ◽  
Performance Variations

SUMMARYThis paper discusses the concept and parameter design of a robust stair-climbing compliant modular robot, capable of tackling stairs with overhangs. Geometry modifications of the periphery of the wheels of our robot helped in tackling overhangs. Along with establishing a concept design, the robust design parameters are set to minimize performance variations. The Grey-based Taguchi method is applied to provide an optimal setting for the design parameters of the robot. The robot prototype is shown to have successfully scaled stairs of varying dimensions, with overhang, thus corroborating the analysis performed.

scholarly journals Improving health in the military and beyond using salutogenic design

Facilities ◽  
2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Stephanie Brick
Keyword(s):  
Design Theory ◽  
High Stress ◽  
Well Being ◽  
Work Conditions ◽  
Stress Disorders ◽  
Security Requirements ◽  
Service Members ◽  
Concept Design ◽  
Design Strategies ◽  
Content Type

Purpose Service members of the US Department of Defense (DoD) have alarmingly high rates of depression, anxiety, probable stress disorders and suicidality, all of which are negative health conditions exacerbated by various external stressors. High-stress work conditions – to include shift work, hazardous territories, high-stakes mission sets and generally disconnected sites – require a work environment that facilitates, rather than inhibits, stress reduction and mental well-being. This paper aims to present “salutogenic design” as an innovative approach: Salutogenic design offers demonstrated architectural solutions that improve health and well-being. Design/methodology/approach This paper describes salutogenic design strategies beginning with the need for such an approach, the call to action to implement strategic and tactical solutions and the challenges and financial impacts of such a broad and innovative strategy to improve workplace health, well-being and performance in the DoD and beyond. Examples of these strategies, via biophilic design solutions, are presented in the central Table 1 as an easy-to-reference tool and supported by the voluminous literature as referenced, in part, through this research paper. Findings Salutogenic design strategies offer innovative, financially viable solutions to help mitigate stress and improve workforce well-being while maintaining the highest level of building security requirements in access-controlled spaces and disconnected sites, such as military installations and government compounds. Research limitations/implications Issues of mental and physical health are complex and multi-faceted, and they require complex and multi-faceted solutions. Salutogenic design is presented as one facet of that solution: a tangible solution to an often-intangible issue. Further, as a novel approach to address a critical DoD issue, Table 1 bridges the common gap between high-concept design theory and practical construction-application solutions, with positive value to the health, performance, quality-of-life and well-being of service members. Originality/value To the best of the author’s knowledge, this paper is the first to approach the DoD’s imperative to reduce service members’ mental stress with “salutogenic design.”

Assessment of Influence and Analysis of Mechanism on the Reliability for Solder Joints of Electronic Device

2005 ◽  
Author(s):  
Qiang Yu ◽  
Jae-Chul Jin ◽  
Hirokazu Abe ◽  
Takahiro Koyama ◽  
Tadahiro Shibutani ◽  
...  
Keyword(s):  
Thermal Fatigue ◽  
Solder Joints ◽  
Electronic Device ◽  
Advanced Technology ◽  
Circuit Board ◽  
Design Stage ◽  
Concept Design ◽  
Fatigue Reliability ◽  
Design Engineers ◽  
Design Factors

In recent years, the development of the electronic device using the semiconductor is remarkable. In current advanced technology, it has succeeded in making the package which size is almost equal to the IC chip. Moreover for miniaturization and high integration of the electronic device, it has been fined in soldered joints divisions. As a result, the strength reliability become an important problem, since the thermal fatigue fracture is generated by thermal expansion difference between package and printed-circuit board. However, it is difficult to guarantee quality during the design stage, because it is hard to know which design factors will prolong the fatigue life. So it is needed that a quantitative evaluation technique of the relation between the design change and the thermal fatigue reliability. The authors introduced a simple approach to help solving the design and development of a package system by using the SDSS (statistical design support system) and FEM (Finite Element Method) analysis. In this study, in order to improve the reliability, evaluations of the influence of various design factors on the reliability of BGA (Ball Grid Array) soldered joints were carried out. By using the total equivalent inelastic strain range obtained by FEM analysis, the sensitivity is calculated and the authors got the influence of each design factor. With the results, the design engineers can know the rate of each factors’ effect on the reliability of solder joints and they can use the results to assess the reliability of their design from the concept design stage. Consequently, it can be expected that almost reliability problems can be avoided at the beginning, and it will lead a great advantage of shortening design period and slashing costs. And this will lead design engineers to come up with more new ideas.

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