OPTIMIZATION OF DESIGN SPACE OF SUPPORTING WING RIB, WHICH IS MADE BY DIFFERENT STRUCTURAL MATERIALS

2021 ◽  
pp. 39-46
Author(s):  
T. M. Avdukhina ◽  
A. A. Chubatenko
Keyword(s):  
Design Space ◽  
Safety Margin ◽  
Bending Moment ◽  
Structural Materials ◽  
Modern Method ◽  
Metallic Materials ◽  
Loading Pattern ◽  
Weight Saving ◽  
Scientific Mission ◽  
Structural Calculation

The article describes a possibility of airframe weight-saving structural technique during supporting rib development by design space tailoring. For scientific mission is given below the supporting rib, the loading pattern, the shearingforce and bending-moment diagrams. The researches are undertaken by structural calculation aimed to choosing of the supporting rib design space, web thickness, a number of supporting carrier gates. Herewith, it should be noted that requirements of structural availability without crippling and attainment of safety margin are achieved. Calculation and optimization of supporting rib design space held for supporting rib, which is made of different metallic materials. The article says, that usage of modern method of airframe assembly allows to optimize the design spaces of supporting rib and reduce the weight of it. According to researches, analysis of total resulting is done, and recommendations for use are given.

Leakage Analysis of a High Pressure Flange Connection Under Bending Moments: An Analytic Procedure

2014 ◽  
Author(s):  
Matthias Bortz ◽  
Rolf Wink
Keyword(s):  
High Pressure ◽  
Contact Pressure ◽  
Fluid Pressure ◽  
Safety Margin ◽  
Bending Moment ◽  
Operating Conditions ◽  
Bending Moments ◽  
Spherical Lens ◽  
Flange Connection ◽  
Bolt Stress

High pressure flange connections for LDPE plants are designed using lens ring gaskets and bolted flange connections. The sealing principle is to achieve a high contact pressure between the spherical lens shape and the conical tube end. This contact pressure must exceed the fluid pressure by a safety margin under all operating conditions. Bending moments acting on the flange connection will create an uneven distribution of contact pressure over the lens ring surface. In this paper a procedure is shown to analyse the influence of the bending moment under consideration of internal pressure on a flange connection using 3-dimensional finite element models. The variations in bolt stress and distribution of contact pressures due to the bending moment are of specific interest. A first approach will be provided to derive some simplified design rules regarding leakage assessment of such flange connections.

Plastic Collapse Load for Vessel With External Flaw Simultaneously Subjected to Internal Pressure and External Bending Moment: Experimental and FEA Results

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Shinji Konosu ◽  
Masato Kano ◽  
Norihiko Mukaimachi ◽  
Hiroyuki Komura ◽  
Hiroyuki Takada
Keyword(s):  
Internal Pressure ◽  
Yield Stress ◽  
Pressure Ratio ◽  
Safety Margin ◽  
Bending Moment ◽  
Plastic Instability ◽  
Plastic Collapse ◽  
Collapse Load ◽  
The Status ◽  
Work Done

This paper is based on work done to establish the validity of a simple engineering approach to assess plastic collapse for a vessel with a local thin area (LTA). The approach is based on a recently developed p-M (internal pressure ratio and external bending moment ratio) diagram, which is an easy way to visualize the status of a vessel with a LTA simultaneously subjected to internal pressure, p and external bending moment, M due to earthquake, etc. If the assessment point (Mr,pr) lies inside the p-M line, the vessel with the LTA is judged to be safe. Numerous experiments and finite element analyses for a cylinder with an external flaw were conducted under (1) pure internal pressure, (2) pure external bending moment, and (3) subjected simultaneously to both internal pressure and external bending moment, in order to determine the plastic initiation load and plastic collapse load by applying the twice-elastic slope (TES) as recommended by ASME. It has been clarified that the collapse (TES) loads are similar to those calculated under the proposed p-M line based on the measured yield stress. The p-M line adopted in the Ibaraki fitness for service (FFS) rule based on the specified minimum yield stress with a safety factor of 1.5 indicates that the safety margin for the plastic initiation loads at LTA is about 1.0–3.0, about 1.5–4.0 for the TES loads at LTA, and 2.5–6.5 for the plastic instability (break) loads.

Seismic Behavior of Shear Wall-Frame Systems Considering Foundation Stiffness

2017 ◽  
Vol 17 (03) ◽  
pp. 1750041 ◽  
Author(s):  
Bo Di ◽  
Xueyi Fu
Keyword(s):  
Seismic Behavior ◽  
Safety Margin ◽  
Bending Moment ◽  
Shear Wall ◽  
Internal Force ◽  
Shallow Foundation ◽  
Frame Structure ◽  
Base Shear ◽  
Internal Forces ◽  
Frame Systems

In this paper, the influence of foundation stiffness on the seismic behavior of shear wall-frame systems was investigated. First, a basic differential equation was established to account for the interaction between the foundation and superstructure. By solving the equation, the influence of foundation stiffness on the lateral stiffness, inter-story drift, and internal force distribution of the superstructure at the elastic stage was elucidated. Subsequently, the concept and method for determining the range of foundation stiffness suitable for shear wall-frame systems were proposed. By taking a 12-story shear wall-frame structure built on a shallow foundation as an example, a parametric study was performed for various frame-to-wall relative stiffness ratios and foundation stiffnesses. The effect of shallow foundation stiffness on the base shear distribution and energy dissipation of the superstructure was clarified, with results compared with those of the fixed-base model. The analysis results indicated that the degeneration of foundation stiffness due to earthquake damages will result in significant redistribution of internal forces, namely, the internal forces of the walls decrease, while those of the frames increase. In particular, the shear-force and bending moment of the bottom frame columns rise drastically, which may greatly reduce the safety margin and should be considered in practical design.

Assessment of Hull Monitoring Measurements for a Large Blunt Vessel

2013 ◽  
Author(s):  
Gaute Storhaug ◽  
Ole Jakob Hareide
Keyword(s):  
North Atlantic ◽  
Safety Margin ◽  
Bending Moment ◽  
Original Design ◽  
The North ◽  
Industry Standard ◽  
Design Life ◽  
Collapse Strength ◽  
The North Atlantic ◽  
Wave Induced

A large blunt vessel was designed for a longer target life than usual in world-wide trade. Due to experience with whipping and springing, special attention to these effects was also made during the design and approval in order to ensure satisfactory strength of the vessel. The vessel was consequently strengthened beyond the minimum industry standard, and it has now been operated for several years. The owner/operator who observed wave induced vibrations (whipping/springing) onboard, equipped the vessel with a hull monitoring system from a recognized supplier. After a few years of measurements, the data was sent to DNV for assessment of the effect of the vibrations and the consequence for the particular design. The data shows that the vessel has been trading in more demanding areas than assumed during design, but the environment is less severe than the North Atlantic. The measured fatigue life based on a stress concentration factor of 2.0 has been estimated to be well below the design life, so special attention to cracks need to be taken from now on if the trade remains the same in the future. No cracks have, however, been identified so far during inspection. The vessel has also experienced two severe storms. The maximum loading level has been higher than ever assessed by DNV before based on hull monitoring data of blunt vessels. The rule of thumb value of 20% increase on extreme loading for blunt vessels due to whipping has been exceeded. The wave bending moment according to IACS URS11 has also been exceeded without whipping. The ultimate collapse strength has been assessed and compared to the measured dynamic loading and allowable still water loading. When whipping is assumed fully effective to contribute to collapse, the safety margin is still above 1.0, but on the borderline of what is desirable. However, if the vessel had not been strengthened beyond the original design due to the concern of whipping and springing, the safety margin would have been below 1.0. This may be the first documentation of a vessel that has been saved from breaking in two due to addressing springing and whipping properly during design.

Plastic Collapse Load for Vessel With External Flaw Simultaneously Subjected to Internal Pressure and External Bending Moment: Experimental and FEA Results

2007 ◽  
Author(s):  
Shinji Konosu ◽  
Masato Kano ◽  
Norihiko Mukaimachi ◽  
Hiroyuki Komura ◽  
Hiroyuki Takada
Keyword(s):  
Internal Pressure ◽  
Yield Stress ◽  
Safety Factor ◽  
Safety Margin ◽  
Bending Moment ◽  
Plastic Instability ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Rule Based ◽  
Minimum Yield

The newly-developed p-M diagram provides a means for readily evaluating the collapse load of pressure equipment with external flaws simultaneously subjected to internal pressure, p and external bending moment, M due to earthquake, etc. In this paper, numerous experiments and FEAs for a cylinder with an external flaw were conducted under (1) pure internal pressure, (2) pure external bending moment, and (3) subjected simultaneously to both internal pressure and external bending moment, in order to determine the plastic initiation load and plastic collapse load by applying the twice-elastic slope (TES) as recommended by ASME. It has been clarified that the collapse (TES) loads are much the same as those calculated under the proposed p-M line based on the measured yield stress. The p-M line adopted in the Ibaraki FFS rule based on the specified minimum yield stress with a safety factor of 1.5 indicates that the safety margin for the plastic initiation loads at LTA is about 1.0–3.0, about 1.5–4.0 for the TES loads at LTA and 2.5–6.5 for the plastic instability (break) loads.

scholarly journals Evaluation of Driving Performance of Two Types of Competitive Wheelchairs for Badminton Made of Two Different Metallic Materials

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 161
Author(s):  
Masaki Nonaka ◽  
Hoshi Kashiwazaki ◽  
Soichiro Ura ◽  
Masahito Nagamori ◽  
Hisashi Uchiyama ◽  
...  
Keyword(s):  
Composite Material ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Specific Weight ◽  
Functional Improvement ◽  
Metallic Materials ◽  
Aluminum Composite ◽  
Weight Saving ◽  
Significant Difference

Currently, various types of wheelchairs for badminton have been developed for weight saving and functional improvement. The purpose of this study was to evaluate each performance of two types of competitive wheelchairs for badminton made of two different metallic materials. One of the wheelchairs used in this study was made of magnesium composite material, which was 45 GPs of Young’s modulus, 1.738 g/cm3 of the specific weight, and 9.57 kg of weight. Another was made of scandium-aluminum composite material, which was 70 GPa of Young’s modulus, 2.70 g/cm3 of the specific weight, and 10.81 kg of weight. The frames and weights of the wheelchairs were similar. In this experiment, the subject’s electromyograms from six muscles in driving each wheelchair were measured and analyzed. Furthermore, the motion in driving was captured and analyzed using a three-dimensional motion capture system. This experiment led to the following result: no significant difference was found in wheelchair performance due to the different materials.

scholarly journals Influence of the stiffness of beam-column connections on the structural analysis of reinforced concrete buildings

2018 ◽  
Vol 11 (4) ◽  
pp. 834-855
Author(s):  
J. B. SANTOS ◽  
T. J. DA SILVA ◽  
G. M. S. ALVA
Keyword(s):  
Reinforced Concrete ◽  
Structural Analysis ◽  
Concrete Structures ◽  
Bending Moment ◽  
Analytical Models ◽  
Reinforced Concrete Structures ◽  
Overall Stability ◽  
Partial Transfer ◽  
Structural Calculation ◽  
Real Behavior

Abstract Conventional structural analysis of buildings in reinforced concrete is performed considering beam-column connections as rigid. However, experimental results prove the existence of relative rotations in beam-column connections of reinforced concrete structures, showing the partial transfer of bending moment. In this study the influence of the stiffness of beam-column connections on the global stability and in the column bending moments of buildings in reinforced concrete was investigated. A building was designed with rigid connections and deformable connections to identify the importance of considering the influence of the stiffness of the beam-column connections in the overall stability of monolithic and in the redistribution efforts in reinforced concrete structures. In order to determine the stiffness rotation of deformable connections, two analytical models available in literature were used, and a comparison between the results obtained by each analytical model was also performed. Based on the results, it is concluded that neglecting the influence of the stiffness of the beam-column connections on the analysis of monolithic reinforced concrete structures may result in different solutions compared to the real behavior of the structure. The stiffness values obtained with the analytical models usually differ from the condition of rigid connections, suggesting an adjustment on the standard consideration of rigid connections adopted by the computer programs of structural calculation.

SEM Examination of a Used Diamond Knife

1971 ◽  
Vol 29 ◽  
pp. 452-453
Author(s):  
J. Temple Black
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
High Magnification ◽  
Metallic Materials ◽  
Wide Spread ◽  
Thin Sections ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron ◽  
Diamond Knife

Since its introduction by Fernandez-Moran, the diamond knife has gained wide spread usage as a common material for cutting of thin sections of biological and metallic materials into thin films for examination in the transmission electron microscope. With the development of high voltage E.M. and scanning transmission E.M., microtomy applications will become increasingly important in the preparation of specimens. For those who can afford it, the diamond knife will thus continue to be an important tool to accomplish this effort until a cheaper but equally strong and sharp tool is found to replace the diamond, glass not withstanding.In Figs. 1 thru 3, a first attempt was made to examine the edge of a used (β=45°) diamond knife by means of the scanning electron microscope. Because diamond is conductive, first examination was tried without any coating of the diamond. However, the contamination at the edge caused severe charging during imaging. Next, a thin layer of carbon was deposited but charging was still extensive at high magnification - high voltage settings. Finally, the knife was given a light coating of gold-palladium which eliminated the charging and allowed high magnification micrographs to be made with reasonable resolution.

Observation of secondary slip systems in tungsten bicrystals

1984 ◽  
Vol 42 ◽  
pp. 478-479
Author(s):  
J. R. Fekete ◽  
R. Gibala
Keyword(s):  
Stress Field ◽  
Grain Boundaries ◽  
Deformation Behavior ◽  
Stress Axis ◽  
Polycrystalline Materials ◽  
Slip Systems ◽  
Metallic Materials ◽  
Twist Boundary ◽  
Secondary Slip ◽  
Plane Normal

The deformation behavior of metallic materials is modified by the presence of grain boundaries. When polycrystalline materials are deformed, additional stresses over and above those externally imposed on the material are induced. These stresses result from the constraint of the grain boundaries on the deformation of incompatible grains. This incompatibility can be elastic or plastic in nature. One of the mechanisms by which these stresses can be relieved is the activation of secondary slip systems. Secondary slip systems have been shown to relieve elastic and plastic compatibility stresses. The deformation of tungsten bicrystals is interesting, due to the elastic isotropy of the material, which implies that the entire compatibility stress field will exist due to plastic incompatibility. The work described here shows TEM observations of the activation of secondary slip in tungsten bicrystals with a [110] twist boundary oriented with the plane normal parallel to the stress axis.

The limits of human performance

2008 ◽  
Vol 44 ◽  
pp. 11-26 ◽  
Author(s):  
Ralph Beneke ◽  
Dieter Böning
Keyword(s):  
Human Performance ◽  
Safety Margin ◽  
Afferent Input ◽  
Metabolic Energy ◽  
Human Organism ◽  
Mechanical Resistance ◽  
As Doping ◽  
Gene And Protein Expression ◽  
Underlying Mechanisms ◽  
Biochemical Research

Human performance, defined by mechanical resistance and distance per time, includes human, task and environmental factors, all interrelated. It requires metabolic energy provided by anaerobic and aerobic metabolic energy sources. These sources have specific limitations in the capacity and rate to provide re-phosphorylation energy, which determines individual ratios of aerobic and anaerobic metabolic power and their sustainability. In healthy athletes, limits to provide and utilize metabolic energy are multifactorial, carefully matched and include a safety margin imposed in order to protect the integrity of the human organism under maximal effort. Perception of afferent input associated with effort leads to conscious or unconscious decisions to modulate or terminate performance; however, the underlying mechanisms of cerebral control are not fully understood. The idea to move borders of performance with the help of biochemicals is two millennia old. Biochemical findings resulted in highly effective substances widely used to increase performance in daily life, during preparation for sport events and during competition, but many of them must be considered as doping and therefore illegal. Supplements and food have ergogenic potential; however, numerous concepts are controversially discussed with respect to legality and particularly evidence in terms of usefulness and risks. The effect of evidence-based nutritional strategies on adaptations in terms of gene and protein expression that occur in skeletal muscle during and after exercise training sessions is widely unknown. Biochemical research is essential for better understanding of the basic mechanisms causing fatigue and the regulation of the dynamic adaptation to physical and mental training.

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