scholarly journals Laser Scanner-Based 3D Digitization for the Reflective Shape Measurement of a Parabolic Trough Collector

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5607
Author(s):  
Gabriele Guidi ◽  
Umair Shafqat Malik ◽  
Andrea Manes ◽  
Stefano Cardamone ◽  
Massimo Fossati ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Element Model ◽  
Parabolic Trough ◽  
Element Analysis ◽  
Optical Efficiency ◽  
Parabolic Trough Collector ◽  
Parabolic Surface

In concentrated solar power technology, the precise shape of the reflective surfaces is crucial for efficiency. Considering the geometry and size of a parabolic trough collector, measuring the actual shape is not trivial and some techniques can only be adopted during the assembly operations, evaluating only the manufacturing and alignment processes. The method proposed and tested in this work exploits a laser scanner-based three-dimensional digitization technique that can be used without any marker or other tools, and is attached to the structure. This technique is particularly suitable for assessing the behavior and the optical efficiency of the collectors under load and for validating a finite element model of the structure. The method defines the shape of the parabolic surface by collecting a 3D point cloud of the parabolic surface using a laser scanner. The measured form can then be compared with the ideal shape obtained from a finite element analysis of the structure subject to the gravity field. The comparison can also be performed when the collector is loaded by known forces or torques, with the finite element model reproducing the actual loading scenario. The object of the case study of this work was a 12 m wide full-scale prototype trough collector manufactured at the Politecnico di Milano. The uncertainty of the 3D measurements, acquiring twelve images in different positions, was verified to be less than 3.6 mm.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

scholarly journals Finite element and biomechanical analysis of risk factors for implant failure during tension band plating

2020 ◽  
Vol 48 (11) ◽  
pp. 030006052097207
Author(s):  
Jing Ding ◽  
Fei Wang ◽  
Fangchun Jin ◽  
Zhen-kai Wu ◽  
Pin-quan Shen
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Biomechanical Model ◽  
Element Model ◽  
Tension Band ◽  
Biomechanical Analysis ◽  
Implant Failure ◽  
Element Analysis

Objective Tension band plating has recently gained widespread acceptance as a method of correcting angular limb deformities in skeletally immature patients. We examined the role of biomechanics in procedural failure and devised a new method of reducing the rate of implant failure. Methods In the biomechanical model, afterload (static or cyclic) was applied to each specimen. The residual stress of the screw combined with different screw sizes and configurations were measured and compared by X-ray diffraction. With regard to static load and similar conditions, the stress distribution was analyzed according to a three-dimensional finite element model. Results The residual stress was close to zero in the static tension group, whereas it was very high in the cyclic load group. The residual stress of screws was significantly lower in the convergent group and parallel group than in the divergent group. The finite element model showed similar results. Conclusions In both the finite element analysis and biomechanical tests, the maximum stress of the screw was concentrated at the position where the screws enter the cortex. Cyclic loading is the primary cause of implant failure.

INVESTIGATION OF DAMAGE ON DERBENDIKHAN DAM DURING EARTHQUAKE EXCITATION

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Cagri Mollamahmutoglu ◽  
Idris Bedirhanoglu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Main Body ◽  
Damage Development ◽  
Element Analysis ◽  
Rock Fill ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this study, the performance of a damaged dam was evaluated through a three-dimensional finite element model. The dam is located in Derbendikhan city of Northern Iraq and damaged during a 7.3 magnitude earthquake which was happened 30 kilometers south of Halabja city. Derbendikhan dam which was built between the years 1956-1961 is a clay-core rock fill dam. The damage of the dam was investigated at the site right after the earthquake and some cracks were observed in the main body of the dam. The main goal of this work is to present the results of the survey which was conducted at the site and investigating the damage development mechanism through a realistic three-dimensional finite element model of the dam. As complying with the observations at the site, the finite element analysis has shown that the primary failure mechanism is due to the separation of the core and rock fill sections at the downstream side of the dam.

Precision Machines: Diagnostics of Vibration Through Modal and Finite Element Analysis

1991 ◽  
Author(s):  
V. Prakash ◽  
R. J. Montague
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Test Model ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Structure Correlation ◽  
Three Dimensional Finite Element ◽  
Precision Machines

Abstract This paper presents the diagnostics of the effects of vibration on the precise placement of electronic components in a surface mount assembly process. Experimental Modal Analysis using present day software/hardware as well as a three dimensional finite element model are performed on the machine structure. Correlation between the experiment and finite element model are also performed and the strength of using the finite element model as a test model for contemplating any design alterations are presented.

Parametric Analysis Mechanical Properties of Bolted Joints

2010 ◽  
Vol 97-101 ◽  
pp. 3924-3927 ◽  
Author(s):  
Da Zhao Yu ◽  
Yue Liang Chen ◽  
Zhong Hu Jia ◽  
Yong Gao ◽  
Wen Lin Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Three-dimensional finite element model of a bolted joint has been developed in the non-linear finite element code MSC.Marc and attempts were made to validate it by comparing results with those of experiments and other finite element. Issues in modeling the contact between the joint parts, which affect the accuracy and efficiency of the model, were presented. Experimental measurements of surface strains and load transfer ratio(LTR) were compared with results from finite element analysis. The results show that three-dimensional finite element model of bolted joint can produce results in close agreement with experiment. Three-dimensional effects such as bolt titling, seconding and through-thickness variations in stress and strain are well represented by such models. Three-dimensional finite element analysis was also used to study the effects of different parameters on the mechanical behaviour of single lap bolted joints. The results show that straight hole, small bolt diameter, and big hole pitch are selected first for bolted joint if other conditions allowed, and effect of bolt material on LTR of joint is small for small load. Interference and pre-stress should be strictly controlled for bolted joints in order to attain the best fatigue capability of lap joint.

scholarly journals Establishment of a Finite Element Model and Biomechanical Analysis of Different Fixation Methods for Total Talar Prosthesis Replacement

2021 ◽  
Author(s):  
Qian dong Yang ◽  
Le Chang ◽  
Xuting Bian ◽  
Lin Ma ◽  
Tao Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Screw Fixation ◽  
Articular Surface ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Ankle Motion ◽  
Fixation Methods ◽  
Without Screws

Abstract Back ground：A three-dimensional finite element model of the whole foot with high geometric similarity was established and used to simulate the conditions after whole talar prosthesis implantation with several fixation methods, including Screw fixation of subtalar+talus-navicular joint, fixation with screws at only the subtalar joint, and fixation without screws. The biomechanical characteristics of the talus prosthesis were assessed in different gait phases to guide the selection of surgical methods in clinical practice.Methods：With the three-dimensional CT data of a volunteer's foot, Mimics13.0 and Geomagic10.0 software were used to carry out geometric reconstruction of the ankle-related tissues, and Hypermesh10.0 software was used for grid division and material attribute selection. Finally, the data were imported into Abaqus 6.9, and the simulated screw data were applied to different models. Finite element models with different fixation methods were simulated, and the stresses exerted by the human body in three gait phases (heel-strike, midstance and push-off) were simulated. The pressure changes in the articular surface around the talus or the prosthesis, the micromotion of the talus and the prosthesis and ankle motion were measured. Results：Finite element analysis on the biomechanical mechanism showed that screw fixation of the prosthesis in different gait phases mainly increases the pressure on the tibialis articular surface as well as decreases the pressure on the fused articular surface and joint micromotion, which hinders ankle motion. The indicator values were nearly the same in the models of fixation without screws and the normal state.Conclusion：The 3D finite element model created in this study has been verified to be an accurate and reliable model. The biomechanical mechanism varies by fixation method according to finite element analysis. Fixation of the prosthesis without screws yields values most similar to normal values.

Finite element buckling analysis of laminated composite sandwich panels with transversely flexible core carrying attached elastic strip

2012 ◽  
Vol 14 (6) ◽  
pp. 715-733
Author(s):  
Karamat Malekzadeh Fard ◽  
Alireza Sayyidmousavi ◽  
Zouheir Fawaz ◽  
Habiba Bougherara
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Sandwich Panels ◽  
Element Model ◽  
Attached Mass ◽  
Element Analysis ◽  
The Core ◽  
The Face

In this article, a three-dimensional finite element model is proposed to study the effect of distributed attached mass with thickness and stiffness on the buckling instability of sandwich panels with transversely flexible cores. Unlike the previous works in the literature which have made use of unified displacement theories, the present model uses different types of finite elements to model the core and the face sheets. It utilizes shell elements for the face sheets and three-dimensional solid elements for the core which enables the model to account for the transverse flexibility of the structure. The motions of the face sheets and the core as well as the attached mass are related through defining constraint equations between the nodes of their respective finite elements based on the concept of master and slave nodes which is incorporated into the finite element analysis program ANSYS through a user-defined subroutine. The validated finite element model is then used to study the effects of size, thickness, material property, aspect ratio, and the position of the attached mass on the buckling load of a sandwich panel under different combinations of boundary conditions. The results presented in this study have hitherto not been reported in the literature.

Evaluation of sternum closure methods by means of a nonlinear finite element analysis

2019 ◽  
Vol 233 (12) ◽  
pp. 1282-1291 ◽  
Author(s):  
Suleyman Nazif Orhan ◽  
Mehmet Hamit Ozyazicioglu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Plastic Material ◽  
Steel Wire ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Computed Tomography Images ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The main purpose of this study is to develop a validated three-dimensional finite element model of sternum closure techniques. For this aim, the finite element method analysis results of three closure methods were compared with experimental test results. Also, three more closure techniques are simulated numerically to study the effect of the number of wires used in the manubrium and xiphoid regions. A three-dimensional model of polyurethane sternum foam was created based on computed tomography images. Six different closure techniques using steel wire, steel bands and ZipFix bands were modeled on the sternum and transferred into a three-dimensional finite element model. The sternum was modeled as an isotropic bilinear-elasto-plastic material, and nonlinear contact conditions were applied. The models were analyzed under lateral distraction loading, and load-displacement curves were obtained from displacements at the incision line. Allowable loads and stiffness values of the methods were evaluated from these curves. The results showed the importance of the including material as well as geometric nonlinearities in the simulations to obtain realistic results from the numerical analyses. Also, the analyses showed that closures that include steel or ZipFix bands are superior to conventional wiring, and addition of a single wire at the manubrium and xiphoid regions significantly improved the efficiency of the closure techniques.

Analysis on Oil Extraction Progressing Cavity Pump Three-Dimensional Finite Element Model

2014 ◽  
Vol 644-650 ◽  
pp. 670-673
Author(s):  
Guo You Han ◽  
Ming Qi Wang ◽  
Yu Hou ◽  
Qiang Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Analysis Model ◽  
Element Analysis

The finite element analysis of PCP involves three nonlinear of geometry, material and contact, and the load of PCP is diversity, leading to it difficult to establish the finite element model and calculate by finite method. This article takes GLB120-27 as an example, to establish 3D solid model of PCP by using SolidWorks; to determine M-R model constant of stator rubber by using the data of uniaxial tensile test: to separate the seal band from the stator chamber by using Boolean operation and set up contact pairs, to achieve the correct simulation of stator chamber fluid pressure; to correctly simulate the interference fit between stator and rotor through setting correlation parameters; to establish 3D finite element analysis model and verify the correctness by using the experiment data of hydraulic characteristics of PCP.

Finite Element Simulation and Dynamic Test of the Bridge Structure

2011 ◽  
Vol 52-54 ◽  
pp. 2191-2196
Author(s):  
Yu Qing Liu ◽  
Yan Xiang Wu ◽  
Hai Bo Huo
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Dynamic Test ◽  
Element Model ◽  
Scientific Basis ◽  
Element Analysis ◽  
Structural Dynamic ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, we established a bridge three-dimensional finite element model for the structural dynamic analysis according to the geometry and material properties of a bridge Li Gong Yi Qiao at Wuhan University of Technology. On the other hand, we tested the dynamic characteristics of the bridge under environmental excitation by means of bridge sensors arranged at different points. The modal parameters of the bridge were identified through fitting the admittance circle. The comparison between the measured results and the theoretical studies has shown that the low-order vibration frequency and mode obtained from finite element analysis generally consistent with those from test. The finite element model provides a scientific basis for condition monitoring of the bridge in actual operations.

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