scholarly journals The Optimization of Ti Gradient Porous Structure Involves the Finite Element Simulation Analysis

2021 ◽  
Vol 8 ◽  
Author(s):  
Bowen Liu ◽  
Wei Xu ◽  
Xin Lu ◽  
Maryam Tamaddon ◽  
Mingying Chen ◽  
...  
Keyword(s):  
Porous Structure ◽  
Bone Tissue ◽  
Equivalent Stress ◽  
Stress And Strain ◽  
Porous Implant ◽  
Element Simulation ◽  
Oral Environment ◽  
Maximum Equivalent Stress ◽  
Cubic Structure ◽  
Surrounding Bone

Titanium (Ti) and its alloys are attracting special attention in the field of dentistry and orthopedic bioengineering because of their mechanical adaptability and biological compatibility with the natural bone. The dental implant is subjected to masticatory forces in the oral environment and transfers these forces to the surrounding bone tissue. Therefore, by simulating the mechanical behavior of implants and surrounding bone tissue we can assess the effects of implants on bone growth quite accurately. In this study, dental implants with different gradient pore structures that consisted of simple cubic (structure a), body centered cubic (structure b) and side centered cubic (structure c) were designed, respectively. The strength of the designed gradient porous implant in the oral environment was simulated by three-dimensional finite element simulation technique to assess the mechanical adaptation by the stress-strain distribution within the surrounding bone tissue and by examining the fretting of the implant-bone interface. The results show that the maximum equivalent stress and strain in the surrounding bone tissue increase with the increase of porosity. The stress distribution of the gradient implant with a smaller difference between outer and inner pore structure is more uniform. So, a-b type porous implant exhibited less stress concentration. For a-b structure, when the porosity is between 40 and 47%, the stress and strain of bone tissue are in the range of normal growth. When subject to lingual and buccal stresses, an implant with higher porosity can achieve more uniform stress distribution in the surrounding cancellous bone than that of low porosity implant. Based on the simulated results, to achieve an improved mechanical fixation of the implant, the optimum gradient porous structure parameters should be: average porosity 46% with an inner porosity of 13% (b structure) and outer porosity of 59% (a structure), and outer pore sized 500 μm. With this optimized structure, the bone can achieve optimal ingrowth into the gradient porous structure, thus provide stable mechanical fixation of the implant. The maximum equivalent stress achieved 99 MPa, which is far below the simulation yield strength of 299 MPa.

Influence on Fatigue and Biomechanics of Cone Fit of Dental Implant around the Surrounding Bone Tissue

2016 ◽  
Vol 872 ◽  
pp. 281-286
Author(s):  
Lei Liu ◽  
Xiao Zhang ◽  
Yu Feng Zhou ◽  
Xian Shuai Chen ◽  
Ya Ling Wang
Keyword(s):  
Bone Tissue ◽  
Dental Implant ◽  
Equivalent Stress ◽  
Load Force ◽  
Vertical Load ◽  
Vertical Cone ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Maximum Equivalent Stress ◽  
Surrounding Bone

In this paper, the purpose is to compare three different cone fit of dental implant around the surrounding bone tissue that influence on fatigue and biomechanics, it is also to provide a theoretical basis for the design and clinical application of dental implant. The method is that loading the force 100N and 200N with different angle to the three different cone with dental implant with the finite element analysis (FEA) that analyzes the stress and fatigue in ideal conditions. The Results is that when the loading is vertical, cone for 3 degrees of the implant have the best performance. The cone for 80 degrees of the implant is min among the max equivalent stress of the implants. However, comprehensive view, Cone for 24 degrees of the implant the most stable. we find that cone of different implant when subjected to the same force the maximum equivalent stress is different, smaller conical implant under vertical load force have good performance, but with the increase of the loading angle the bigger conical implant performance better.

Finite-Element Analysis and Optimization for Gradient Porous Structure of Artificial Bone

2012 ◽  
Vol 271-272 ◽  
pp. 922-926 ◽  
Author(s):  
Yan Mei Qi ◽  
Li Jun Yang ◽  
Li Li Wang
Keyword(s):  
Mechanical Properties ◽  
Porous Structure ◽  
Equivalent Stress ◽  
Strain Analysis ◽  
Equivalent Strain ◽  
Stress And Strain ◽  
Artificial Bone ◽  
Element Analysis ◽  
Maximum Equivalent Stress ◽  
Ansys Workbench

The loading force of the artificial bone implanted into the human body and the flowing, growth and deposition of cells were influenced by the gradient porous structure. The software of ANSYS Workbench was used in the paper for the stress and strain analysis of the gradient porous structure of the established 3D artificial bone. The variation of the maximum equivalent stress and maximum equivalent strain and elastic modulus changed through the changing of the loading force and porosity. Basis on meeting the mechanical properties, the porosity was used as the index for the optimization of the porous structure of the artificial bone. And it also laid the foundation for the subsequent laser sintering.

scholarly journals Deformation Investigations on the Flexspline with the Conic Curve Combined Cam Wave Generator

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Shuyan Wang ◽  
Dongxiang Guo ◽  
Shiteng Mao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equivalent Stress ◽  
Mathematic Model ◽  
Transmission Efficiency ◽  
Experimental Results ◽  
Stress And Strain ◽  
Element Analysis ◽  
Wave Generator ◽  
Maximum Equivalent Stress

The deformation of the flexspline and the meshing quality are largely determined by the profile of a wave generator. The wave generator with a combined profile can effectively reduce or improve the deformation stress and strain of the flexspline for improving the transmission efficiency and reducing wear or noise. In this paper, in view of the facts that conic is originally cut out of the cone and different conic curves are easy to transform, a design concept of the curve cam wave generator based on the conic curve is proposed. Firstly, the combined principle, constraint conditions, and mathematic model of the curve cam generator based on the conic curve are established. Secondly, the deformation theory of the flexspline acted by the curve cam wave generator with conic curves has been developed, and finite element analysis on stress and strain of the flexspline compared with a standard elliptic wave generator has been carried out. Finally, a cam wave generator combined with the circle and ellipse as a sample has been developed and manufactured. Circumferential strain test has been further carried out by a static strain gauge to verify the strain characteristics of the flexspline acted with the circle and ellipse combined cam wave generator. The FEM results show that, in the meshing area of the flexspline, the maximum equivalent stress of the flexspline under the action of the arc and the ellipse wave generator is about 93 MPa, which is 36.3% lower than the maximum equivalent stress of the flexspline under the action of the standard ellipse which is 143 MPa. The experimental results show that the fitting curve of the experimental results fits well with the finite element analysis curve.

Dynamic Load Simulation Analysis of Hemp Stalk

2013 ◽  
Vol 303-306 ◽  
pp. 2724-2726
Author(s):  
Xue Qiang Liu ◽  
Jian Chun Zhang ◽  
Hao Zhang ◽  
Xin Hu
Keyword(s):  
Feeding Rate ◽  
Rotation Speed ◽  
Simulation Analysis ◽  
Equivalent Stress ◽  
Stress And Strain ◽  
Ansys Software ◽  
Bast Fiber ◽  
Maximum Equivalent Stress ◽  
The Difference ◽  
Load Simulation

The distribution of maximum equivalent stress on hemp stalks at different roller speeds were scavenged by LS-PREPOST function. The stress and strain distributions of hemp stalk under the transversely even-distributed load are analyzed through ANSYS software. The results show that hemp decortication largely depended on the rotation speed of separation roller and the feeding rate. In addition, the failure degree of bast fiber, the maturity and the water content of the stalk, and the difference in mechanical properties and geometrical size should be also taken into account.

The Effects of Bony Structure Simplification Methods on the Biomechanics of Tibiofemoral Joint in Series of Flexion Angles

2012 ◽  
Vol 163 ◽  
pp. 70-73
Author(s):  
Hai Dong Zheng ◽  
Rong Ying Huang ◽  
Hong Guang Zheng ◽  
Yun Fei Guo
Keyword(s):  
Bone Tissue ◽  
Equivalent Stress ◽  
Material Models ◽  
Tibiofemoral Joint ◽  
Bony Structure ◽  
Femoral Cartilage ◽  
Maximum Equivalent Stress ◽  
In Series ◽  
Structure Simplification ◽  
Single Material

To investigate the effects of bony structure simplification methods on the biomechanics of tibiofemoral joint under compression and torsion effects in series of flexion angles, the MRI images of the normal human knee at flexion angles of 0°/25°/60°/80° were developed through SONATA MAESTRO 1.5T, then through the technology of threshold segmentation and registration assembly, bone tissue distinguished models and single material models were built based on these images. The results show that: (1) at the flexion angles of 0°/60°/80°, the maximum equivalent stress on femur and femoral cartilage significantly were slightly higher than single material models, only at 25 °, the maximum equivalent stress of the femoral cartilage in single material model was obviously larger; (2) difference of maximum equivalent stress on tibia and tibial cartilage between two kinds of models was not significant, and stress increased with the increase of flexion angle, only at 80 °, the stress on tibia of bone tissue distinguished models reduced; (3) The skeletal load was borne mainly by the cortical bone.

Simulation and test of the thermal behavior of pressure switch

2018 ◽  
Vol 32 (11) ◽  
pp. 1850138
Author(s):  
Yifang Liu ◽  
Daner Chen ◽  
Yao Zhang ◽  
Tingting Dai
Keyword(s):  
Thermal Behavior ◽  
Equivalent Stress ◽  
Extreme Temperature ◽  
Simulation Software ◽  
Substrate Thickness ◽  
Test Results ◽  
Element Simulation ◽  
Deformation Law ◽  
Maximum Equivalent Stress ◽  
Pressure Switch

Little, lightweight, low-power microelectromechanical system (MEMS) pressure switches offer a good development prospect for small, ultra-long, simple atmosphere environments. In order to realize MEMS pressure switch, it is necessary to solve one of the key technologies such as thermal robust optimization. The finite element simulation software is used to analyze the thermal behavior of the pressure switch and the deformation law of the pressure switch film under different temperature. The thermal stress releasing schemes are studied by changing the structure of fixed form and changing the thickness of the substrate, respectively. Finally, the design of the glass substrate thickness of 2.5 mm is used to ensure that the maximum equivalent stress is reduced to a quarter of the original value, only 154 MPa when the structure is in extreme temperature (80[Formula: see text]C). The test results show that after the pressure switch is thermally optimized, the upper and lower electrodes can be reliably contacted to accommodate different operating temperature environments.

scholarly journals Design and Mechanical Properties Verification of Gradient Voronoi Scaffold for Bone Tissue Engineering

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 664
Author(s):  
Haiyuan Zhao ◽  
Yafeng Han ◽  
Chen Pan ◽  
Ding Yang ◽  
Haotian Wang ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Tissue Engineering ◽  
Elastic Modulus ◽  
Porous Structure ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Voronoi Tessellation ◽  
Impact Resistance ◽  
Natural Bone ◽  
The Impact

In order to obtain scaffold that can meet the therapeutic effect, researchers have carried out research on irregular porous structures. However, there are deficiencies in the design method of accurately controlling the apparent elastic modulus of the structure at present. Natural bone has a gradient porous structure. However, there are few studies on the mechanical property advantages of gradient bionic bone scaffold. In this paper, an improved method based on Voronoi-tessellation is proposed. The method can get controllable gradient scaffolds to fit the modulus of natural bone, and accurately control the apparent elastic modulus of porous structure, which is conducive to improving the stress shielding. To verify the designed structure can be fabricated by additive manufacturing, several designed models are obtained by SLM and EBM. Through finite element analysis (FEA), it is verified that the irregular porous structure based on Voronoi-tessellation is more stable than the traditional regular porous structure of the same structure volume, the same pore number and the same material. Furthermore, it is verified that the gradient irregular structure has a better stability than the non-gradient structure. An experiment is conducted successfully to verify the stability performance got by FEA. In addition, a dynamic impact FEA is also performed to simulate impact resistance. The result shows that the impact resistance of the regular porous structure, the irregular porous structure and the gradient irregular porous structure becomes better in turn. The mechanical property verification provides a theoretical basis for the structural design of gradient irregular porous bone tissue engineering scaffolds.

scholarly journals Finite Element Modeling of Residual Stress at Joint Interface of Titanium Alloy and 17-4PH Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 629
Author(s):  
Nana Kwabena Adomako ◽  
Sung Hoon Kim ◽  
Ji Hong Yoon ◽  
Se-Hwan Lee ◽  
Jeoung Han Kim
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Modeling ◽  
Equivalent Stress ◽  
Stress Gradient ◽  
Joint Interface ◽  
Element Modeling ◽  
Actual Experiment ◽  
Maximum Equivalent Stress

Residual stress is a crucial element in determining the integrity of parts and lifetime of additively manufactured structures. In stainless steel and Ti-6Al-4V fabricated joints, residual stress causes cracking and delamination of the brittle intermetallic joint interface. Knowledge of the degree of residual stress at the joint interface is, therefore, important; however, the available information is limited owing to the joint’s brittle nature and its high failure susceptibility. In this study, the residual stress distribution during the deposition of 17-4PH stainless steel on Ti-6Al-4V alloy was predicted using Simufact additive software based on the finite element modeling technique. A sharp stress gradient was revealed at the joint interface, with compressive stress on the Ti-6Al-4V side and tensile stress on the 17-4PH side. This distribution is attributed to the large difference in the coefficients of thermal expansion of the two metals. The 17-4PH side exhibited maximum equivalent stress of 500 MPa, which was twice that of the Ti-6Al-4V side (240 MPa). This showed good correlation with the thermal residual stress calculations of the alloys. The thermal history predicted via simulation at the joint interface was within the temperature range of 368–477 °C and was highly congruent with that obtained in the actual experiment, approximately 300–450 °C. In the actual experiment, joint delamination occurred, ascribable to the residual stress accumulation and multiple additive manufacturing (AM) thermal cycles on the brittle FeTi and Fe2Ti intermetallic joint interface. The build deflected to the side at an angle of 0.708° after the simulation. This study could serve as a valid reference for engineers to understand the residual stress development in 17-4PH and Ti-6Al-4V joints fabricated with AM.

scholarly journals Numerical Simulation and Experimental Study on Axial Stiffness and Stress Deformation of the Braided Corrugated Hose

2021 ◽  
Vol 11 (10) ◽  
pp. 4709
Author(s):  
Dacheng Huang ◽  
Jianrun Zhang
Keyword(s):  
Numerical Simulation ◽  
Geometric Model ◽  
Equivalent Stress ◽  
Element Model ◽  
Maximum Error ◽  
Structural Features ◽  
Axial Stiffness ◽  
Frictional Stress ◽  
Maximum Equivalent Stress ◽  
Simulation Results

To explore the mechanical properties of the braided corrugated hose, the space curve parametric equation of the braided tube is deduced, specific to the structural features of the braided tube. On this basis, the equivalent braided tube model is proposed based on the same axial stiffness in order to improve the calculational efficiency. The geometric model and the Finite Element Model of the DN25 braided corrugated hose is established. The numerical simulation results are analyzed, and the distribution of the equivalent stress and frictional stress is discussed. The maximum equivalent stress of the braided corrugated hose occurs at the braided tube, with the value of 903MPa. The maximum equivalent stress of the bellows occurs at the area in contact with the braided tube, with the value of 314MPa. The maximum frictional stress between the bellows and the braided tube is 88.46MPa. The tensile experiment of the DN25 braided corrugated hose is performed. The simulation results are in good agreement with test data, with a maximum error of 9.4%, verifying the rationality of the model. The study is helpful to the research of the axial stiffness of the braided corrugated hose and provides the base for wear and life studies on the braided corrugated hose.

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