A New Ultrasonic Testing Method for Residual Strain Measurement With Laser Grating

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Cuixiang Pei ◽  
Xing Kou ◽  
Tianhao Liu ◽  
Zhenmao Chen
Keyword(s):  
Surface Waves ◽  
Residual Strain ◽  
Ultrasonic Testing ◽  
Strain Measurement ◽  
Element Model ◽  
Testing Method ◽  
Experiment Validation ◽  
Narrow Frequency Band ◽  
The Relationship ◽  
The Finite Element Model

Abstract In this paper, a new and noncontact ultrasonic testing (UT) method using laser grating is proposed for the residual strain measurement. In this method, the laser grating technique is utilized to generate coherent surface waves with a specific wavelength in the narrow frequency band. A numerical method based on the finite element model is established to simulate the coherent surface waves generated by the laser grating in prestrained media to determine the capability and sensitivity of this method. The relationship between the strain and frequency spectrum of the coherent surface wave is studied. Finally, an experiment validation of the laser grating-based UT of residual strain is carried out using specimen with different plastic strains by the tensile test.

scholarly journals Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Xuande Yue ◽  
Luling An ◽  
Xin Ye ◽  
Chufan Wang ◽  
Yuebo Cai ◽  
...  
Keyword(s):  
Stress State ◽  
Strain Measurement ◽  
Strain Field ◽  
Composite Laminates ◽  
Element Model ◽  
Local Damage ◽  
Damage State ◽  
Assembly Structure ◽  
Bolt Connection ◽  
The Finite Element Model

The composite-aluminum hybrid bolted structures are widely used in aircraft. Due to low molding accuracy of composite components, gaps always occur between components during assembly. In this case, the bolt connection can cause a complex strain and stress state of component. It may adversely affect the mechanical properties or cause local damage of the structure. A simplified model of the composite-aluminum assembly structure was established in this paper. Then, the influence of forced assembly, liquid shim, and peelable fiberglass shim on the strain and stress state of the composite-aluminum hybrid bolted structure was studied. A bolt connection experimental device was designed to apply a preload to the specimen. The strain field on the specimen surface was measured using the 3D-DIC strain measurement system. The finite element model was established to study the interlaminar stress and damage state of composite laminates. It is found that the strain of specimen in the X -direction is mainly affected by the bending deformation, while the strain in the Y -direction is mainly affected by the compression of bolt head. For composite laminates, the strain value in the X -direction can be reduced by 8.31%-70.97% with shims. As for the strain value in the Y -direction, the liquid shim can only reduce it up to 23.93%when the gap is large. In addition, the liquid shim and peelable fiberglass shim cannot reduce the stress value of all interlaminar elements, but it can make the stress distribution more uniform and improve the stress state of the interlaminar element when the shim was more than 0.8 mm.

Analysis of Affecting Factors of Ground Deformation Based on Shield Tunnel Excavation

2013 ◽  
Vol 441 ◽  
pp. 615-618
Author(s):  
Li Xin Li ◽  
Qi Yun Zou ◽  
Jun Jia Wang
Keyword(s):  
Ground Deformation ◽  
Ground Surface ◽  
Surface Displacement ◽  
Element Model ◽  
Shield Tunnel ◽  
Affecting Factors ◽  
Tunnel Excavation ◽  
Tunnel Diameter ◽  
The Relationship ◽  
The Finite Element Model

The shield tunnel method is a way that widely used in tunnel build. However, the ground surface displacement and deformation because of tunnel excavation will bring a series of affections in our engineering. By using the finite element model of different tunnel excavation depth, different elastic modulus and different tunnel diameter of the tunnel, we predicted it correctly. Finally, we get the relationship between the surface displacement and the depth of tunnel excavation, diameter, strength of soil.

Study on the Influence Depth of Subgrade of Airport Runway under Different Loads of Plane

2013 ◽  
Vol 645 ◽  
pp. 440-444
Author(s):  
Xian Min Zhang ◽  
Xuan Bao ◽  
Zhang Wei
Keyword(s):  
System Theory ◽  
Finite Element ◽  
Finite Element Model ◽  
Fundamental Frequency ◽  
Elastic Layer ◽  
Element Model ◽  
Layer System ◽  
Airport Runway ◽  
The Relationship ◽  
The Finite Element Model

The thickness of the subgrade model has great impact on the frequency when analyzing the fundamental frequency of the runway by the finite element model, and airport runway under different model of plane will has different influence depth of subgrade. In this paper, an airport runway finite element model, which is base on elastic layer system theory, is established to be loaded different model of plane. The results show that the influence depth of subgrade under different aircraft types, as well as the relationship curves of the influence depth and frequency.

Engineering Mechanics Analysis of Pigging for S Elbow of Oil-Gas Pipe

2013 ◽  
Vol 700 ◽  
pp. 128-131
Author(s):  
Shang Na Song ◽  
Ming Zeng ◽  
Wen Ming Wang ◽  
Shi Min Zhang ◽  
Da Yu ◽  
...  
Keyword(s):  
Element Model ◽  
Operating Parameters ◽  
Mechanics Analysis ◽  
Transmission Pipeline ◽  
Pipeline Project ◽  
Engineering Mechanics ◽  
The Impact ◽  
Oil Gas ◽  
The Relationship ◽  
The Finite Element Model

S elbow in Zhijing River is one of the key parts in the East Gas Transmission Pipeline Project. It brings a great deal of uncertainty and risk factors for pipeline pigging operations. By analysis on dynamic of pig pigging and the impact over bending, this paper established the finite element model, simulated pigging process on the condition that the operating parameters of the pipeline pigging operations were given, analyzed the relationship among pipeline pressure, foam pigging speed and pipe stress, then obtained the security of pipeline pigging operations.

Cyclic Triaxial Tests of Saturated Clay and Stability Numerical Analysis of Inland Waterway Slope under Effect of Ship Wave

2012 ◽  
Vol 268-270 ◽  
pp. 629-636
Author(s):  
Yuan Zhan Wang ◽  
Xu Fei Liu ◽  
Zhi Kai Zhang ◽  
Dian Guang Ma
Keyword(s):  
Shear Strength ◽  
Cyclic Loading ◽  
Residual Strain ◽  
Element Model ◽  
Triaxial Tests ◽  
Cyclic Triaxial ◽  
Ship Wave ◽  
Saturated Clay ◽  
Inland Waterway ◽  
The Relationship

Ship wave is one of the key factors that affect slope stability of inland waterway because of scour and corrosion. In this paper, the investigations on the softening index, the residual strain and the shear strength with cyclic loading of saturated clay were carried out through cyclic triaxial shear tests in conditions of three different ambient pressures in Naji area on the upper reaches of You River in Guangxi. The relationship between softening index and vibration times, the relationship between residual strain and vibration times as well as the shear strength discounting ratio curve varying with cyclic loading were obtained. Based on the tests, the finite element model of inland waterway slope was founded to analyze the stability of inland waterway slope under effect of ship wave.

Study on Joint Deflection of Existing Joint Plain Concrete Pavement upon Adoption of Hot Mixture Asphalt Overlay

2011 ◽  
Vol 462-463 ◽  
pp. 253-258
Author(s):  
Jing Song Shan ◽  
Zhong Yin Guo
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Plain Concrete ◽  
Element Model ◽  
Basic Mechanism ◽  
Concrete Pavement ◽  
Reflection Cracking ◽  
Asphalt Overlay ◽  
The Relationship ◽  
The Finite Element Model

When HMA (hot mixture asphalt) is used to remedy functional or structural deficiencies of existing JPCP (joint plain concrete pavement), reflection cracking is a major distress mode in HMA overlay. The basic mechanism of reflection cracking is the propagation of cracks through the overlay due to deflection difference in the joints vicinity of the existing pavements. In this paper the model of JPCP is created by three finite element method and the relationship between joint deflection difference and effects such as base modulus, elastic coefficient of spring elements is discussed. Based on the model of JPCP, the finite element model of asphalt overlay is created then and shear stress concentration phenomenon is found at the bottom of HMA where is just above the joint of JPCP. So, the rule of the shear stress at the bottom of HMA with deflection difference at the joint of JPCP is studied.

Research on Structure Size of Muffler to the Influence of Acoustic Properties

2013 ◽  
Vol 341-342 ◽  
pp. 366-370
Author(s):  
Jin Ku Li
Keyword(s):  
Finite Element ◽  
Noise Reduction ◽  
Volume Ratio ◽  
Element Model ◽  
Acoustic Properties ◽  
Structure Parameters ◽  
Resonant Structure ◽  
Acoustic Performance ◽  
The Relationship ◽  
The Finite Element Model

The dimention for muffler has great impact on the car engine. Based on software GAMBIT, GT-POWER,SYSNOISE,through comprehensively using finite element and boundary element method,simulating and analyzing the acoustic performance for the basic noise reduction unit,establishing the finite element model, comparing the frequency and noise reduction of different volume ratio of cavity and throat tube.Simulation analysis and experimental results show that the resonant structure parameters have a direct effect on its resonant frequency and noise reduction amount. the relationship characteristic between them is that the ratio more bigger,the requency and noise reduction amount more bigger , too.And draw the two relation formulas through calculation.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Durability Analysis of the Reduction Gear for High Speed Train Considering Driving Histories

2012 ◽  
Vol 586 ◽  
pp. 269-273
Author(s):  
Chul Su Kim ◽  
Gil Hyun Kang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Element Model ◽  
Rolling Stock ◽  
Reduction Gear ◽  
High Speed Train ◽  
Analysis Software ◽  
Tractive Effort ◽  
Durability Analysis ◽  
The Finite Element Model

To assure the safety of the power bogies for train, it is important to perform the durability analysis of reduction gear considering a variation of velocity and traction motor capability. In this study, two types of applied load histories were constructed from driving histories considering the tractive effort and the train running curves by using dynamic analysis software (MSC.ADAMS). Moreover, this study was performed by evaluating fatigue damage of the reduction gears for rolling stock using durability analysis software (MSC.FATIGUE). The finite element model for evaluating the carburizing effect on the gear surface was used for predicting the fatigue life of the gears. The results showed that the fatigue life of the reduction gear would decrease with an increasing numbers of stops at station.

Analysis of Hydroelectric Unit’s Upper Bracket Based on Test and FEM

2014 ◽  
Vol 721 ◽  
pp. 131-134
Author(s):  
Mi Mi Xia ◽  
Yong Gang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Element Analysis ◽  
Hydroelectric Unit ◽  
The Finite Element Analysis ◽  
Strain Rosette ◽  
The Finite Element Model

To research the load upper bracket of Francis hydroelectric unit, then established the finite-element model, and analyzed the structure stress of 7 operating condition points with the ANSYS software. By the strain rosette test, acquired the data of stress-strain in the area of stress concentration of the upper bracket. The inaccuracy was considered below 5% by analyzing the contradistinction between the finite-element analysis and the test, and match the engineering precision and the test was reliable. The finite-element method could be used to judge the stress of the upper bracket, and it could provide reference for the Structural optimization and improvement too.

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