Depth feature extraction of surface-breaking defects using laser pulsed thermography

2021 ◽  
Vol 63 (5) ◽  
pp. 265-272
Author(s):  
Jiaqi Liu ◽  
Zhijie Zhang ◽  
Chenyang Zhao ◽  
Ningchen Dong ◽  
Zhenyu Lin
Keyword(s):  
Feature Extraction ◽  
Structural Steel ◽  
Simulation Analysis ◽  
Element Model ◽  
Observation Point ◽  
Defect Depth ◽  
Exponential Relationship ◽  
Pulsed Thermography ◽  
Contrast Method ◽  
Depth Feature

In this paper, the feasibility of the depth feature extraction of surface-breaking defects based on laser pulsed thermography in transmission mode is proposed. This method is adopted to detect the depth of surface-breaking defects. First, a finite element model based on COMSOL is established to simulate structural steel specimens with different defect depths and the contrast method is used to detect these depths. In order to verify its feasibility, the model is simulated at different time nodes. A simulation analysis shows the practicability of this method. Then, through an artificial slot depth feature extraction experiment on structural steel specimens, an algorithm is used to denoise an infrared image and then the contrast method is used to extract the defect depth feature, which verifies the feasibility of the method. The experimental results show that as the depth of artificial slots increases, the temperature at the observation point also reduces. The best fitting equation of the defect depth and the temperature at the observation point at a certain heating time have an exponential relationship. This method can accurately detect defect depths.

Simulation Analysis of Secondary-Load Rc Square Columns Strengthened with IFRP

2014 ◽  
Vol 501-504 ◽  
pp. 578-582
Author(s):  
Liang Hsu ◽  
Ming Long Hu ◽  
Jun Zhi Zhang
Keyword(s):  
Finite Element ◽  
Simulation Analysis ◽  
Element Model ◽  
Fiber Reinforced Polymer ◽  
Experimental Result ◽  
Compression Process ◽  
Reinforced Polymer ◽  
Secondary Load ◽  
The Impact ◽  
The Finite Element Model

Considering secondary load, simulate the axial compression process of reinforced concrete square columns strengthened with igneous rock fiber reinforced polymer with Abaqus. Make a comparison between the simulation result and experimental result. The finite-element model can simulate the experiment preferably. And the impact of lagged strain is very obvious.

Finite Element Simulation Analysis on Space KX-Joint

2014 ◽  
Vol 915-916 ◽  
pp. 146-149
Author(s):  
Yong Sheng Wang ◽  
Li Hua Wu
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Simulation Analysis ◽  
Local Buckling ◽  
Element Model ◽  
Ansys Software ◽  
Element Simulation ◽  
Calculation Results ◽  
Buckling Failure ◽  
The Finite Element Model

The finite element model of the space KX-Joint was established using ANSYS software, and the failure mode and ultimate bearing capacity of KX-joint were researched. Calculation results show that the surface of chord wall on the roots of compression web members was into the plastic in K plane, and the holding pole without the plastic area and the local buckling failure happened in the surface of chord wall on the roots of Compression Web Members in X plane; The bearing capacity of the joint increased with the Chord diameter, which was appears in the form of power function.

Numerical Simulation Analysis for Enclosure Piles Cracking of a Deep Pit Foundation

2011 ◽  
Vol 109 ◽  
pp. 276-280
Author(s):  
Ji Chao Zhang ◽  
Yong Kang Yang ◽  
Yong Xu
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Element Model ◽  
Wind Load ◽  
Load Direction ◽  
Foundation Pit ◽  
Deep Pit ◽  
Disadvantageous Factors ◽  
Construction Condition ◽  
The Finite Element Model

Based on the appearance of crack of enclosure piles on a foundation pit, Midas GTS is adopted to establish the finite element model. Through the numerical simulation, the influence of the direction of wind load, wind scale and prestress of anchor are analyzed, the worst wind load direction, unfavorable construction condition, maximum moment of enclosure piles are ensured, crack width in different disadvantageous factors are calculated, which provides a guide for continuous construction.

Analysis of stress intensity factor for fatigue crack using bootstrap S-version finite element model

2020 ◽  
Vol 11 (4) ◽  
pp. 579-589
Author(s):  
Muhamad Husnain Mohd Noh ◽  
Mohd Akramin Mohd Romlay ◽  
Chuan Zun Liang ◽  
Mohd Shamil Shaari ◽  
Akiyuki Takahashi
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Finite Element Model ◽  
Simulation Analysis ◽  
Element Model ◽  
Bootstrap Resampling ◽  
Confidence Bounds ◽  
Content Type ◽  
Resampling Method ◽  
The Mean

PurposeFailure of the materials occurs once the stress intensity factor (SIF) overtakes the material fracture toughness. At this level, the crack will grow rapidly resulting in unstable crack growth until a complete fracture happens. The SIF calculation of the materials can be conducted by experimental, theoretical and numerical techniques. Prediction of SIF is crucial to ensure safety life from the material failure. The aim of the simulation study is to evaluate the accuracy of SIF prediction using finite element analysis.Design/methodology/approachThe bootstrap resampling method is employed in S-version finite element model (S-FEM) to generate the random variables in this simulation analysis. The SIF analysis studies are promoted by bootstrap S-version Finite Element Model (BootstrapS-FEM). Virtual crack closure-integral method (VCCM) is an important concept to compute the energy release rate and SIF. The semielliptical crack shape is applied with different crack shape aspect ratio in this simulation analysis. The BootstrapS-FEM produces the prediction of SIFs for tension model.FindingsThe mean of BootstrapS-FEM is calculated from 100 samples by the resampling method. The bounds are computed based on the lower and upper bounds of the hundred samples of BootstrapS-FEM. The prediction of SIFs is validated with Newman–Raju solution and deterministic S-FEM within 95 percent confidence bounds. All possible values of SIF estimation by BootstrapS-FEM are plotted in a graph. The mean of the BootstrapS-FEM is referred to as point estimation. The Newman–Raju solution and deterministic S-FEM values are within the 95 percent confidence bounds. Thus, the BootstrapS-FEM is considered valid for the prediction with less than 6 percent of percentage error.Originality/valueThe bootstrap resampling method is employed in S-FEM to generate the random variables in this simulation analysis.

scholarly journals Simulation Analysis of Knee Ligaments in the Landing Phase of Freestyle Skiing Aerial

2019 ◽  
Vol 9 (18) ◽  
pp. 3713 ◽  
Author(s):  
Yanming Fu ◽  
Xin Wang ◽  
Tianbiao Yu
Keyword(s):  
Knee Joint ◽  
Mechanical Response ◽  
Simulation Analysis ◽  
Cruciate Ligament ◽  
Knee Injuries ◽  
Element Model ◽  
Knee Joints ◽  
Internal Stresses ◽  
Risk Of Injury ◽  
Medium Risk

The risk of knee injuries in freestyle skiing athletes that perform aerials is high. The internal stresses in the knee joints of these athletes cannot easily be directly measured. In order to ascertain the mechanical response of knee joints during the landing phase, and to explore the mechanism of damage to the cartilage and ligaments, a finite element model of the knee joint was established. Three successful landing conditions (neutral, backward, or forward landing) from a triple kicker were analyzed. The results demonstrate that the risk of cruciate ligament damage during a neutral landing was lowest. A forward landing carried medium risk, while backward landing was of highest risk. Backward and forward landing carried risk of injury to the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), respectively. The magnitude of stress on the meniscus and cartilage varied for all three landing scenarios. Stress was largest during neutral landing and least in backward landing, while forward landing resulted in a medium level of stress. The results also provide the basis for training that is scientifically robust so as to reduce the risk of injury and assist in the development of a professional knee joint protector.

The Application of Moldflow in Injection Mold Design of Mobile Phone Cover

2011 ◽  
Vol 228-229 ◽  
pp. 542-547
Author(s):  
Wen Jian Zhang ◽  
Qi Zhang
Keyword(s):  
Mobile Phone ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Mold Design ◽  
Injection Mold ◽  
Three Dimensional Model ◽  
Molding Process ◽  
Injection Mold Design ◽  
Cae Technology

Based the CAE technology, the paper introduced the application of Moldflow Insight in injection mold design of mobile phone cover. First, we must preprocess the finite element model, including importing three-dimensional model, meshing, and process setting. And then, we can use preliminary simulation analysis to determine the number and location of the gate. Finally to filling, cooling, packing and warpage analysis for part which can help us to find the causes from warpage generated. By optimizing the molding process parameters, adjusting the dwell pressure and the dwell time we can get less warpage, which can meet the precision demand of parts, consequently, the result can provide gist for the mold designers to design and for the injection molding technologist to process parameter adjustment.

Simulation Analysis of Isolation about Spray Boom

2014 ◽  
Vol 900 ◽  
pp. 742-745 ◽  
Author(s):  
Yao Jie He ◽  
Bai Jing Qiu ◽  
Ya Fei Yang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Modal Analysis ◽  
Simulation Analysis ◽  
Element Model ◽  
The Finite Element Model

In order to attenuate the deformation of spray boom, a finite element model built based on ANSYS, according to the reasults of numerical modal analysis and modal texting, the reliability of the finite element model was affirmed. Then, an isolator was introduced between spray boom and frame, a frame-isolator-spray boom model was built in ADAMS. The effect of the isolators which have different parameters was research, the reasult shows: The isolator has much effect on attenuating spray booms deformation, the stiffness of isolators spring dampers has little effect on spray booms deformation, but the damping of isolators spring dampers has effect on spray booms deformation.

scholarly journals Analysis and Research on the Comprehensive Performance of Vehicle Magnetorheological Regenerative Suspension

Vehicles ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 576-588
Author(s):  
Jinhui Huang ◽  
Enrong Wang ◽  
Hailong Zhang
Keyword(s):  
Simulation Analysis ◽  
Element Model ◽  
Suspension System ◽  
Vehicle Engineering ◽  
Joint Simulation ◽  
Natural Resonance ◽  
Permanent Magnet Linear Motor ◽  
The Stability ◽  
Natural Resonance Frequency ◽  
Suspension Performance

Magnetorheological (MR) regenerative suspension system can not only achieve excellent comprehensive suspension performance but also effectively recover and utilize vibration potential energy, which has been a research hotspot in the field of vehicle engineering. In this paper, for the 1/4 vehicle’s MR regenerative suspension system parallel with a tubular permanent magnet linear motor (TPMLM), the dynamic model of the MR semi-active suspension system and the TPMLM finite element model are established separately to form a joint simulation platform. The simulation analysis of the comprehensive suspension performance and regeneration performance under different road excitations is performed. The results show that installing TPMLM does not change the natural resonance frequency of the suspension system, which ensures good driving comfort and handling stability. At the same time, it has considerable regeneration power. This research can provide a reference for the stability analysis and popularization of the vehicle’s MR regenerative suspension system.

Analysis of the crashworthiness design and collision dynamics of a subway train

2019 ◽  
Vol 234 (10) ◽  
pp. 1117-1128
Author(s):  
Suchao Xie ◽  
Xuanjin Du ◽  
Hui Zhou ◽  
Da Wang ◽  
Zhejun Feng
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Mechanical Performance ◽  
Simulation Analysis ◽  
Element Model ◽  
Collision Dynamics ◽  
Element Analysis ◽  
Static Compression ◽  
Subway Train ◽  
Energy Absorbing

In this study, the crashworthiness of a subway train was assessed by establishing a finite element model for the first three carriages of the train and the track using the Hypermesh software. By utilising the *MAT_HONEYCOMB material model, a honeycomb in an anti-climbing energy-absorbing device was simulated. Moreover, the process of a subway train – travelling at a speed of 25 km/h – colliding with another identical train in a stationary and non-braking state was simulated by employing the finite element analysis software Hypermesh and LS-DYNA. The process of simulation analysis was divided into two parts: (1) analysis of the anti-climbing energy-absorbing devices under static compression for the investigation of energy absorption and (2) collision analysis of the whole train. The contributions of the proposed energy-absorbing structure – at the end of driver’s cab, the coupler and draft gears on each section – to the overall energy absorption in a train collision were calculated. Furthermore, based on the EN15227 standard, the crashworthiness of the train with respect to the survival space for occupants, train acceleration and uplift of wheels relative to the track was evaluated. The coupler of the first carriage fails in a collision at 25 km/h, and the coupler and draft gear are the main energy-absorbing devices. *MAT_HONEYCOMB was used to define the honeycomb materials in anti-climbing energy-absorbing devices and could simulate the mechanical performance thereof. The crashworthiness of the train meets the relevant standard requirements.

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