Reliability Design Method for Interference Joint in Mechanical Engineering

2008 ◽  
Vol 44-46 ◽  
pp. 773-778
Author(s):  
Shi Chao Xiu ◽  
Q. Feng ◽  
Shi Qiang Gao
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Contact Stress ◽  
Mechanical Engineering ◽  
Design Method ◽  
Reliability Design ◽  
Machining Precision ◽  
Joint Structure ◽  
Main Form ◽  
Practical Design

The plastic deformation as a main form of failure of Interference Joints may happen in engineering works if it is designed unreasonably. In this paper, the contact stress and the strength of Interference Joint parts were analyzed deeply. Based on the theory of the reliability design, the general formulas and the method of the reliability design and computation for Interference Joint were established in consideration of joint structure, machining precision, interference value, mechanical properties of the joint parts and their randomicity. The practical design method, which would promote the reliability of Interference Joint effectively, was proposed for larger size and some other important Interference Joints. Compared to the conventional design method, the working reliability of Interference Joints can be improved obviously by means of the reliability design method.

The Fundamental Mechanical Characteristics Evaluation for Bolted Pipe Flange Connections With RTJ Gaskets Under Internal Pressure

2019 ◽  
Author(s):  
Kenshiro Nakade ◽  
Koji Sato ◽  
Toshiyuki Sawa
Keyword(s):  
Plastic Deformation ◽  
Contact Stress ◽  
Inflection Point ◽  
Mechanical Characteristics ◽  
Design Method ◽  
Leak Rate ◽  
Bolt Preload ◽  
Higher Temperature ◽  
Sealing Mechanism ◽  
Better Than

Abstract Bolted pipe flange connections with metallic flat gaskets or ring type joint (RTJ) gaskets are used under higher pressure and higher temperature. However, a sealing mechanism is not known and a design method is not established how to determine bolt preload for preventing leakage from the connection with metallic gaskets. In addition, the characteristics of the connection are not known when oval and octagonal gaskets are used. In previous paper, when the contact stress of metallic flat gasket reaches the stress at plastic deformation inflection point, the leak rate is decreased rapidly. However, the leak rate could be measured up to 1.0 × 10−5 Pa · m3/s level. The objectives of the paper are to measure the leak rate of the metallic flat gasket of which the contact stress is over the stress at plastic deformation inflection point, and to measure the leak rate of 1.0 × 10−9∼10 Pa · m3/s level in the flat metallic gasket in the platen tests and the connection with RTJ gaskets. In addition, the characteristics of the connection are examined when oval and octagonal gaskets are used. As a result, it is found that the leak rate for the metallic flat gasket can be measured around 1.0 × 10−9∼10 Pa · m3/s in the platen tests when the contact stress of aluminum gasket reaches the stress at plastic deformation inflection point and more while the leak rate of SUS 304 flat gasket is around 1.0 × 10−7∼8 Pa · m3/s even if the contact stress is over 1.3 times of the stress at plastic deformation inflection point. In addition, the sealing characteristics of the connection with oval gasket are shown to be better than that with octagonal gasket. From a laser microscope observation, it is found that the contact area of oval gasket in the connection is smaller than that of octagonal gasket in the connection.

INFLUENCE OF THE MECHANICAL PROPERTIES ON THE WEAR BEHAVIOR OF a-C FILMS: AN ENERGY DESCRIPTION

2019 ◽  
Vol 27 (03) ◽  
pp. 1950117
Author(s):  
LI GUO ◽  
MINGJIONG ZHANG ◽  
JIANQIANG HU ◽  
ZHIBIN LU ◽  
GUANGAN ZHANG ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Energy Dissipation ◽  
Contact Stress ◽  
Wear Behavior ◽  
Critical Value ◽  
Friction Test ◽  
Film Properties ◽  
Dissipation Model ◽  
Film Failure

An energy dissipation model was raised, including the influence of film properties, counterpart, contact stress and adhesion strength between film and substrate. A new plastic deformation-tendency index was introduced. The new index was more appropriate in predicting the wear behavior of a-C films than hardness and H/E. Particularly, the critical value of the new index existed for film failure in the friction test. Realizing the limitation of the model, some improvement directions of the model were also discussed in this study.

Severe plastic deformation of Al-1%Cu Alloy processed by a Simple Cyclic Extrusion Compression technique

2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Behavior ◽  
Cast Alloy ◽  
Surface Hardness ◽  
Grain Structure ◽  
Compression Technique ◽  
Cu Alloy ◽  
Cyclic Extrusion Compression

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals Influence of Hydrostatic Extrusion on the Mechanical Properties of the Model Al-Mg Alloys

2021 ◽  
Author(s):  
Aleksandra Towarek ◽  
Wojciech Jurczak ◽  
Joanna Zdunek ◽  
Mariusz Kulczyk ◽  
Jarosław Mizera
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Microstructural Analysis ◽  
Tensile Tests ◽  
Hydrostatic Extrusion ◽  
Microstructure Formation ◽  
Initial State ◽  
Degree Of Deformation ◽  
Al Mg Alloys

AbstractTwo model aluminium-magnesium alloys, containing 3 and 7.5 wt.% of Mg, were subjected to plastic deformation by means of hydrostatic extrusion (HE). Two degrees of deformation were imposed by two subsequent reductions of the diameter. Microstructural analysis and tensile tests of the materials in the initial state and after deformation were performed. For both materials, HE extrusion resulted in the deformation of the microstructure—formation of the un-equilibrium grain boundaries and partition of the grains. What is more, HE resulted in a significant increase of tensile strength and decrease of the elongation, mostly after the first degree of deformation.

scholarly journals Microstructural Characterization and Mechanical Properties of Ti-6Al-4V Alloy Subjected to Dynamic Plastic Deformation Achieved by Multipass Hammer Forging with Different Forging Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xiurong Fang ◽  
Jiang Wu ◽  
Xue Ou ◽  
Fuqiang Yang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Optical Microscope ◽  
Strain Rates ◽  
Materials Properties ◽  
Forging Process ◽  
Hammer Forging ◽  
Dynamic Plastic Deformation

Dynamic plastic deformation (DPD) achieved by multipass hammer forging is one of the most important metal forming operations to create the excellent materials properties. By using the integrated approaches of optical microscope and scanning electron microscope, the forging temperature effects on the multipass hammer forging process and the forged properties of Ti-6Al-4V alloy were evaluated and the forging samples were controlled with a total height reduction of 50% by multipass strikes from 925°C to 1025°C. The results indicate that the forging temperature has a significant effect on morphology and the volume fraction of primary α phase, and the microstructural homogeneity is enhanced after multipass hammer forging. The alloy slip possibility and strain rates could be improved by multipass strikes, but the marginal efficiency decreases with the increased forging temperature. Besides, a forging process with an initial forging temperature a bit above β transformation and finishing the forging a little below the β transformation is suggested to balance the forging deformation resistance and forged mechanical properties.

scholarly journals Tailoring a Low Young Modulus for a Beta Titanium Alloy by Combining Severe Plastic Deformation with Solution Treatment

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3467
Author(s):  
Anna Nocivin ◽  
Doina Raducanu ◽  
Bogdan Vasile ◽  
Corneliu Trisca-Rusu ◽  
Elisabeta Mirela Cojocaru ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Solution Treatment ◽  
Young Modulus ◽  
Orthopedic Implants ◽  
Beta Titanium Alloy

The present paper analyzed the microstructural characteristics and the mechanical properties of a Ti–Nb–Zr–Fe–O alloy of β-Ti type obtained by combining severe plastic deformation (SPD), for which the total reduction was of etot = 90%, with two variants of super-transus solution treatment (ST). The objective was to obtain a low Young’s modulus with sufficient high strength in purpose to use the alloy as a biomaterial for orthopedic implants. The microstructure analysis was conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) investigations. The analyzed mechanical properties reveal promising values for yield strength (YS) and ultimate tensile strength (UTS) of about 770 and 1100 MPa, respectively, with a low value of Young’s modulus of about 48–49 GPa. The conclusion is that satisfactory mechanical properties for this type of alloy can be obtained if considering a proper combination of SPD + ST parameters and a suitable content of β-stabilizing alloying elements, especially the Zr/Nb ratio.

Quasi-static mechanical properties of novel generalized Resch-pattern composite foldcores

2020 ◽  
pp. 095440622094000
Author(s):  
Antao Deng ◽  
Bin Ji ◽  
Xiang Zhou
Keyword(s):  
Mechanical Properties ◽  
Design Method ◽  
Absorption Capacity ◽  
Woven Fabrics ◽  
Geometric Design ◽  
Honeycomb Core ◽  
Reinforced Plastic ◽  
Static Mechanical ◽  
Laminate Thickness ◽  
Static Mechanical Properties

A new geometric design method for foldcores based on the generalized Resch patterns that allow face-to-face bonding interfaces between the core and the skins is proposed. Based on the geometric design method, a systematic numerical investigation on the quasi-static mechanical properties of the generalized Resch-based foldcores made of carbon fiber-reinforced plastic (CFRP) woven fabrics subjected to compression and shear loads is performed using the finite element method that is validated by experiments. The relationships between the mechanical properties and various geometric parameters as well as laminate thickness of the generalized Resch-based CFRP foldcores are revealed. Additionally, the mechanical properties of the generalized Resch-based CFRP foldcore are compared to those of the standard Resch-based, Miura-based foldcore, the honeycomb core, and the aluminum counterpart. It is found that the generalized Resch-based CFRP foldcore performs more stably than the honeycomb core under compression and has higher compressive and shear stiffnesses than the standard Resch-based and Miura-based foldcores and absorbs as nearly twice energy under compression as the Miura-based foldcore does. When compared with the aluminum counterpart, the CFRP model has higher weight-specific stiffness and strength but lower energy absorption capacity under shearing. The results presented in this paper can serve as the useful guideline for the design of the generalized Resch-based composite foldcore sandwich structures for various performance goals.

Influence of Melt Temperature on Compressive Plasticity of a Cu-Zr-Al Bulk Metallic Glass

2010 ◽  
Vol 146-147 ◽  
pp. 517-521
Author(s):  
Sheng Hui Xie ◽  
Xie Rong Zeng ◽  
Dong Ju Fu ◽  
Lei Zhao ◽  
Qiang Hu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Metallic Glasses ◽  
Mechanical Performance ◽  
Casting Temperature ◽  
Thermal And Mechanical Properties ◽  
Micro Hardness ◽  
Melt Temperature ◽  
Hardness Tests ◽  
Important Solution

Cu47.5Zr47.5Al5 bulk metallic glasses (BMGs) were cast from the melt temperature 1143 to 1373 K. The structure, thermal and mechanical properties of the BMGs were investigated by XRD, DSC, HRTEM, dilatometric measurements, micro-hardness tests and uniaxial compression. The results indicate that the microstructure and mechanical performance of BMGs are closely affected by the casting temperature. Proper casting temperature ensures the BMGs with large relaxed excess free volume (REFV) and nano-crystallites, which favor the plastic deformation in Cu47.5Zr47.5Al5 BMGs. Regulating the preparing parameters is an important solution to good plasticity in BMGs.

Experimental and Theoretical Study of the Contact Mechanics of Five Total Knee Joint Replacements

1995 ◽  
Vol 209 (4) ◽  
pp. 225-231 ◽  
Author(s):  
T Stewart ◽  
Z M Jin ◽  
D Shaw ◽  
D D Auger ◽  
M Stone ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Knee Joint ◽  
Contact Pressure ◽  
Contact Stress ◽  
Linear Elasticity ◽  
Contact Area ◽  
Elasticity Analysis ◽  
Joint Replacements ◽  
Total Knee ◽  
Maximum Contact

The tibio-femoral contact area in five current popular total knee joint replacements has been measured using pressure-sensitive film under a normal load of 2.5 kN and at several angles of flexion The corresponding maximum contact pressure has been estimated from the measured contact areas and found to exceed the point at which plastic deformation is expected in the ultra-high molecular weight polyethylene (UHMWPE) component particularly at flexion angles near 90°. The measured contact area and the estimated maximum contact stress have been found to be similar in magnitude for all of the five knee joint replacements tested. A significant difference, however, has been found in maximum contact pressure predicted from linear elasticity analysis for the different knee joints. This indicates that varying amounts of plastic deformation occurred in the polyethylene component in the different knee designs. It is important to know the extent of damage as knees with large amounts of plastic deformation are more likely to suffer low cycle fatigue failure. It is therefore concluded that the measurement of contact areas alone can be misleading in the design of and deformation in total knee joint replacements. It is important to modify geometries to reduce the maximum contact stress as predicted from the linear elasticity analysis, to below the linear elastic limit of the plastic component.

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