scholarly journals Quantitative Testing of Residual Deformation in Plate with Varying Thickness Based on Nonlinear Ultrasound

2022 ◽  
pp. 110402
Author(s):  
Guoliang Zhao ◽  
Suzhen Liu ◽  
Chuang Zhang ◽  
Liang Jin ◽  
Qingxin Yang
Keyword(s):  
Residual Deformation ◽  
Nonlinear Ultrasound ◽  
Varying Thickness

Investigation of shock-wave deformation history from recovered structure

1986 ◽  
Vol 44 ◽  
pp. 434-435
Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Shock Waves ◽  
Shock Front ◽  
Single Crystals ◽  
Residual Deformation ◽  
Deformation Structure ◽  
Deformation History ◽  
Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

CREDO RADON UA – INFORMATION MODEL FOR CALCULATION OF ROAD CONSTRACTION

2019 ◽  
pp. 34-42
Author(s):  
Volodymyr Karedin ◽  
Nadiya Pavlenko
Keyword(s):  
Design Process ◽  
Static Loading ◽  
Computer Aided Design ◽  
Experimental Studies ◽  
Construction Materials ◽  
Residual Deformation ◽  
Road Construction ◽  
Information Support ◽  
Existing Structures ◽  
Road Pavement

CREDO RADON UA software provides an automated calculation of the strength of the pavement structures of non-rigid and rigid types, as well as the calculation of the strengthening of existing structures. In the article, one can see the main features and functionality of the CREDO RADON UA software, the main points in the calculations according to the new regulations. Information support of the design process includes necessary databases, informational and helping materials that make up the full support of the pavement design process. The concept of CREDO RADON UA 1.0 software is made on the use of elasticity theory methods in calculations of initial information models of pavements. Performing optimization calculations, the roadwear in CREDO RADON UA is designed in such a way that no unacceptable residual deformation occurs under the influence of short-term dynamic or static loading in the working layer of the earth bed and in the structural layers during the lifetime of the structure. The calculation algorithms were made in accordance with the current regulatory documents of Ukraine. CREDO RADON UA software allows user to create information bases on road construction materials and vehicles as part of the traffic flow for calculations. The presented system of automated modeling makes it easier for the customer to control the quality of design solutions, to reasonably assign designs to layers of reinforcement, to quickly make comparisons of calculations of different designs for the optimal use of allocated funds. Prospects for further improvement of the program should be the results of theoretical and experimental studies on filling the databases, which are used as information support for automated design of road structures. Keywords: CREDO RADON UA, road, computer-aided design, repair project, road pavement, strengthening, construction, rigid pavement, elasticity module, a transport stream, calculation method, information support, dynamic or static loading.

Seismic performance evaluation of multi-story CBFs equipped with SMA-friction damping braces

2021 ◽  
pp. 1045389X2098700 ◽  
Author(s):  
Canxing Qiu ◽  
Jiawang Liu ◽  
Jun Teng ◽  
Zuohua Li ◽  
Xiuli Du
Keyword(s):  
Strain Hardening ◽  
Ground Motions ◽  
Residual Deformation ◽  
Martensite Phase ◽  
Friction Damper ◽  
Concentrically Braced Frames ◽  
Friction Damping ◽  
Friction Mechanism ◽  
Building Collapse ◽  
Response Characteristics

Shape memory alloys (SMAs) gained increasing attentions from the perspective of seismic protection, primarily because of their excellent superelasticity, satisfactory damping and high fatigue life. However, the superelastic strain of SMAs has an upper limit, beyond which the material completes the austenite to martensite phase transformation and is followed by noticeable strain hardening. The strain hardening behavior would not only induce high force demand to the protected structures, but also cause unrecoverable deformation. More importantly, the SMAs may fracture if the deformation demand exceeds their capacity under severe earthquakes. In the case of installing SMA braces (SMABs) in the multi-story concentrically braced frames (CBFs), the material failure would lead to the malfunction of SMABs and this further causes building collapse. The friction mechanism could behave as a “fuse” through capping the strength demand at a constant level. Therefore, this paper suggests connecting the SMAB with a friction damper to achieve a novel brace, i.e. the SMA-friction damping brace (SMAFDB). A proof-of-concept test was carried out on a homemade specimen and the test results validated the novel brace behaves in a desirable manner. In addition, to explore the seismic response characteristics of the SMAFDB within structures, a six-story CBF equipped with SMAFDBs was designed and compared against those incorporated with SMABs or friction damping braces (FDBs) at the frequently occurred earthquake (FOE), design basis earthquake (DBE) and maximum considered earthquake (MCE). The comparative results show the SMAFDB is superior to the counterparts. Under the FOE and DBE ground motions, the SMAFDBs successfully eliminated residual deformations as the SMABs do, and achieved identical maximum interstory drift as the FDBs. Under the MCE ground motions, the SMAFDBs not only well addressed the brace failure problem that was possibly encountered in the SMABs, but also better controlled residual deformation than the FDBs.

Exact solution for free vibration analysis of linearly varying thickness FGM plate using Galerkin-Vlasov’s method

2020 ◽  
pp. 146442072098049
Author(s):  
V Kumar ◽  
SJ Singh ◽  
VH Saran ◽  
SP Harsha
Keyword(s):  
Free Vibration ◽  
Variable Thickness ◽  
Vibration Analysis ◽  
Shear Deformation Theory ◽  
Free Vibration Analysis ◽  
Functionally Graded ◽  
Constant Thickness ◽  
Engineering Structures ◽  
Property Variation ◽  
Varying Thickness

The present paper investigates the free vibration analysis for functionally graded material plates of linearly varying thickness. A non-polynomial higher order shear deformation theory is used, which is based on inverse hyperbolic shape function for the tapered FGM plate. Three different types of material gradation laws, specifically: a power (P-FGM), exponential (E-FGM), and sigmoid law (S-FGM) are used to calculate the property variation in the thickness direction of FGM plate. The variational principle has been applied to derive the governing differential equation for the plates. Non-dimensional frequencies have been evaluated by considering the semi-analytical approach viz. Galerkin-Vlasov’s method. The accuracy of the preceding formulation has been validated through numerical examples consisting of constant thickness and tapered (variable thickness) plates. The findings obtained by this method are found to be in close agreement with the published results. Parametric studies are then explored for different geometric parameters like taper ratio and boundary conditions. It is deduced that the frequency parameter is maximum for S-FGM tapered plate as compared to E- and P-FGM tapered plate. Consequently, it is concluded that the S-FGM tapered plate is suitable for those engineering structures that are subjected to huge excitations to avoid resonance conditions. In addition, it is found that the taper ratio is significantly affected by the type of constraints on the edges of the tapered FGM plate. Some novel results for FGM plate with variable thickness are also computed that can be used as benchmark results for future reference.

Influence of anisotropy on creep in functionally graded variable thickness rotating disc

2021 ◽  
pp. 030932472199997
Author(s):  
Kishore Khanna ◽  
Vinay Kumar Gupta ◽  
Neeraj Grover
Keyword(s):  
Axial Direction ◽  
Functionally Graded ◽  
Strain Rates ◽  
Lower Yield ◽  
Rotating Disc ◽  
Creep Response ◽  
Varying Thickness ◽  
Disc Material ◽  
Lower Yield Strength ◽  
Tangential Directions

The study is carried out to develop a mathematical model to analyze creep response of a varying thickness rotating disc made of anisotropic functionally graded 6061Al-SiCw.composite. The thickness and content of reinforcement (SiCw) in the disc are assumed to decrease radially according to power law. The yielding of disc material is according to Hill’s criterion and creeping as per threshold stress based law. The developed model is used to obtain the creep stresses and strain rates in the disc for various types of materials’ anisotropy. The stresses and strain rates are noticed to depend on the materials’ anisotropy. The study reveals that the presence of kind of anisotropy wherein the disc material exhibits lower yield strength toward the radial and tangential directions than the axial direction is beneficial in reducing the creep stresses and creep rates in the disc, in comparison to isotropic FGM disc. An anisotropic FG disc, which has highest and the lowest yield strengths, respectively, along the axial and radial directions shows superior creep response.

Study of modes and deflection for ring shaped plate with varying thickness

2021 ◽  
Author(s):  
Manu Gupta ◽  
Ankit Kumar ◽  
Ajendra Kumar ◽  
Robin ◽  
Anuj Kumar
Keyword(s):  
Varying Thickness

scholarly journals Small-Baseline Approach for Monitoring the Freezing and Thawing Deformation of Permafrost on the Beiluhe Basin, Tibetan Plateau Using TerraSAR-X and Sentinel-1 Data

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4464
Author(s):  
Jing Wang ◽  
Chao Wang ◽  
Hong Zhang ◽  
Yixian Tang ◽  
Xuefei Zhang ◽  
...  
Keyword(s):  
Active Layer ◽  
Surface Deformation ◽  
Residual Deformation ◽  
Dynamic Monitoring ◽  
Tibet Plateau ◽  
Time Lags ◽  
Freezing And Thawing ◽  
Linear Deformation ◽  
Small Baseline ◽  
Qinghai Tibet Plateau

The dynamic changes of the thawing and freezing processes of the active layer cause seasonal subsidence and uplift over a large area on the Qinghai–Tibet Plateau due to ongoing climate warming. To analyze and investigate the seasonal freeze–thaw process of the active layer, we employ the new small baseline subset (NSBAS) technique based on a piecewise displacement model, including seasonal deformation, as well as linear and residual deformation trends, to retrieve the surface deformation of the Beiluhe basin. We collect 35 Sentinel-1 images with a 12 days revisit time and 9 TerraSAR-X images with less-than two month revisit time from 2018 to 2019 to analyze the type of the amplitude of seasonal oscillation of different ground targets on the Beiluhe basin in detail. The Sentinel-1 results show that the amplitude of seasonal deformation is between −62.50 mm and 11.50 mm, and the linear deformation rate ranges from −24.50 mm/yr to 5.00 mm/yr (2018–2019) in the study area. The deformation trends in the Qinghai–Tibet Railway (QTR) and Qinghai–Tibet Highway (QTH) regions are stable, ranging from −18.00 mm to 6 mm. The InSAR results of Sentinel-1 and TerraSAR-X data show that seasonal deformation trends are consistent, exhibiting good correlations 0.78 and 0.84, and the seasonal and linear deformation rates of different ground targets are clearly different on the Beiluhe basin. Additionally, there are different time lags between the maximum freezing uplift or thawing subsidence and the maximum or minimum temperature for the different ground target areas. The deformation values of the alpine meadow and floodplain areas are higher compared with the alpine desert and barren areas, and the time lags of the freezing and thawing periods based on the Sentinel-1 results are longest in the alpine desert area, that is, 86 days and 65 days, respectively. Our research has important reference significance for the seasonal dynamic monitoring of different types of seasonal deformation and the extensive investigations of permafrost in Qinghai Tibet Plateau.

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