An automated procedure to build failure envelopes and model the Mohr-Coulomb criterion in the three-dimensional principal stresses space from polyaxial test data

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

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The Measurement of Stresses in Composites

Powder Diffraction ◽

10.1017/s0885715600011507 ◽

1986 ◽

Vol 1 (2) ◽

pp. 15-21 ◽

Cited By ~ 35

Author(s):

J. B. Cohen

Keyword(s):

Three Dimensional ◽

Stress System ◽

Principal Stresses ◽

Reasonable Time ◽

Complete Measurement ◽

Useful Life ◽

Diffraction Peaks ◽

The Difference ◽

Full Investigation ◽

Hydrostatic Component

AbstractAlthough there is mounting interest in the measurement of stresses in composite materials after fabrication and/or use, few measurements to date have not taken into account the three dimensional nature of the stress system in such materials. Most data give only the net stress, that is, the difference between principal stresses. A procedure for a more complete measurement (in a reasonable time) is developed here, including the separation of macrostresses and microstresses. If time does not permit a full investigation, measurements of the lattice parameters of the component phases provide a simple way to sample the hydrostatic component due to differential thermal contraction. The Barrett-Predecki method of adding filler is particularly promising for stress measurements in those composites whose component phases do not give appropriate diffraction peaks. This procedure could also be used for monitoring stresses during the useful life of such materials.

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Three-dimensional seismic analysis of concrete gravity dams considering foundation flexibility

Mechanics and Mechanical Engineering ◽

10.2478/mme-2021-0012 ◽

2021 ◽

Vol 25 (1) ◽

pp. 88-98

Author(s):

Mokhtar Messaad ◽

Messoud Bourezane ◽

Mohamed Latrache ◽

Amina Tahar Berrabah ◽

Djamel Ouzendja

Keyword(s):

Young’S Modulus ◽

Seismic Analysis ◽

Young's Modulus ◽

Three Dimensional ◽

Shear Stresses ◽

Total System ◽

Dam Reservoir ◽

Principal Stresses ◽

Foundation Soil ◽

North West

Abstract Concrete dams are considered as complex construction systems that play a major role in the context of both economic and strategic utilities. Taking into account reservoir and foundation presence in modeling the dam-reservoir-foundation interaction phenomenon leads to a more realistic evaluation of the total system behavior. The article discusses the dynamic behavior of dam-reservoir-foundation system under seismic loading using Ansys finite element code. Oued Fodda concrete dam, situated at Chlef, in North-West of Algeria, was chosen as a case study. Parametric study was also performed for different ratios between foundation Young's modulus and dam Young's modulus E f /E d (which varies from 0.5 to 4). Added mass approach was used to model the fluid reservoir. The obtained results indicate that when dam Young's modulus and foundation Young's modulus are equal, the foundation soil leads to less displacements in the dam body and decreases the principal stresses as well as shear stresses.

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Analyses of Full-Scale Tank Car Shell Impact Tests

ASME 2007 Rail Transportation Division Fall Technical Conference ◽

10.1115/rtdf2007-46010 ◽

2007 ◽

Cited By ~ 3

Author(s):

Y. H. Tang ◽

H. Yu ◽

J. E. Gordon ◽

M. Priante ◽

D. Y. Jeong ◽

...

Keyword(s):

Finite Element ◽

Test Data ◽

Three Dimensional ◽

Full Scale ◽

Collision Dynamics ◽

Dynamics Modeling ◽

Dynamics Model ◽

Rigid Plastic ◽

Element Analysis ◽

Closed Form Solutions

This paper describes analyses of a railroad tank car impacted at its side by a ram car with a rigid punch. This generalized collision, referred to as a shell impact, is examined using nonlinear (i.e., elastic-plastic) finite element analysis (FEA) and three-dimensional (3-D) collision dynamics modeling. Moreover, the analysis results are compared to full-scale test data to validate the models. Commercial software packages are used to carry out the nonlinear FEA (ABAQUS and LS-DYNA) and the 3-D collision dynamics analysis (ADAMS). Model results from the two finite element codes are compared to verify the analysis methodology. Results from static, nonlinear FEA are compared to closed-form solutions based on rigid-plastic collapse for additional verification of the analysis. Results from dynamic, nonlinear FEA are compared to data obtained from full-scale tests to validate the analysis. The collision dynamics model is calibrated using test data. While the nonlinear FEA requires high computational times, the collision dynamics model calculates gross behavior of the colliding cars in times that are several orders of magnitude less than the FEA models.

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Three-dimensional failure envelopes and the brittle-ductile transition

Journal of Geophysical Research Solid Earth ◽

10.1002/jgrb.50081 ◽

2013 ◽

Vol 118 (4) ◽

pp. 1378-1392 ◽

Cited By ~ 24

Author(s):

Martin P. J. Schöpfer ◽

Conrad Childs ◽

Tom Manzocchi

Keyword(s):

Three Dimensional ◽

Brittle Ductile Transition ◽

Failure Envelopes

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Anisotropic Behavior of Geomaterial under Three-Dimensional Stress States

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.160-162.1425 ◽

2010 ◽

Vol 160-162 ◽

pp. 1425-1431

Author(s):

Kun Yong Zhang ◽

Yan Gang Zhang ◽

Chi Wang

Keyword(s):

Stress State ◽

Principal Stress ◽

Three Dimensional ◽

Complex Stress State ◽

Triaxial Tests ◽

Induced Anisotropy ◽

Principal Stresses ◽

True Triaxial ◽

Stress Effects ◽

Stress Induced Anisotropy

Most soil constitutive models were developed based on the traditional triaxial tests with isotropic assumption, in which the load is applied as the major principal stress direction and the other two principal stresses are symmetric. When such isotropic models are applied to practical analysis, stress induced anisotropy under complex stress state and the middle principal stress effects are often neglected, thus there are many disagreements between the calculated results and the infield testing data. To simulate the practical loading process, true triaxial tests were carried out on geomaterial under three-dimensional stress state. It was found that the stress induced anisotropy effects are remarkable and the middle principal stress effects are obvious because of the initial three-dimensional stress state. Such kind of stress-induced anisotropy could have important impact on the numerical analysis results and should be taken into consideration when developing the constitutive model.

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A Stress Analysis and Strength Evaluation of Scarf Adhesive Joints Subjected to Static Tensile Loading

Design Engineering and Computers and Information in Engineering, Parts A and B ◽

10.1115/imece2006-14232 ◽

2006 ◽

Cited By ~ 1

Author(s):

Toshiyuki Sawa ◽

Masahiro Sasaki ◽

Yuya Hirayama

Keyword(s):

Joint Strength ◽

Three Dimensional ◽

Maximum Principal Stress ◽

Adhesive Joints ◽

Stress Distributions ◽

Principal Stresses ◽

Adhesive Properties ◽

Maximum Value ◽

Static Tensile ◽

Three Dimensional Finite Element

Scarf adhesive joints used in practice. However, the stress distributions and the joints strengths have not yet been fully elucidate. Important issues are how to determine the scarf angle in adherend and how to determine the adhesive properties. In this study, the stress distributions in scarf adhesive joints under static tensile loadings are analyzed using three-dimensional finite-element calculations. In the FEM calculations, the effects of Young's modulus of the adhesive, adhesive thickness, scarf angle of the adherend on the stress distributions at the adhesive interfaces are examined. The maximum principal stresses were calculated at every element at the interfaces. As the results, it is found that the maximum value of the maximum principal stress occurs at the edge of the adhesive interfaces (z=0, 1/s=1). It is also observed that the maximum value of the stress is the smallest, when the scarf angle is 60 degree. In addition, the joint strength is estimated using the interface stress. For the verification of the FEM calculations, the experiments were carried out to measure the strengths and the strains in the joints under static tensile loadings using strain gauges. Fairly good agreements are observed between the numerical and the measured results concerning the joint strength and the strains.

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The relations between the stress in temporomandibular joints and the deviated distances for mandibular asymmetric patients

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/0954411920962392 ◽

2020 ◽

Vol 235 (1) ◽

pp. 109-116

Author(s):

Jingheng Shu ◽

Xin Xiong ◽

Desmond YR Chong ◽

Yang Liu ◽

Zhan Liu

Keyword(s):

Temporomandibular Disorders ◽

Three Dimensional ◽

Control Group ◽

Case Group ◽

Principal Stresses ◽

Biomechanical Stress ◽

Mandibular Asymmetry ◽

Temporomandibular Joints ◽

The Difference ◽

Three Dimensional Finite Element

The study aimed to compare the difference of stress distributions in temporomandibular joints (TMJs) between the patients with mandibular asymmetry and asymptomatic subjects and find the relations between deviated distance and biomechanical stress using three-dimensional finite element method, to give guidance to dentists for correction of mandibular asymmetry. Ten facial symmetric subjects without symptoms of temporomandibular disorders (TMD) and 10 mandibular asymmetric patients were recruited and assigned as the Control and Case group respectively. The FE models of the mandible and maxilla were reconstructed from cone-beam computed tomography (CBCT) images. Muscle forces and boundary conditions were applied to the two groups corresponding to centric and anterior occlusions. The simulation manifested significant differences in stresses of the TMJs between the non-deviated and deviated sides in the Case group under the centric and anterior occlusions. The stresses in the Case group were significantly greater than those in the Control group, especially on the non-deviated side. Besides, there were weak and moderate correlations between the third principal stresses and deviated distances for the patients under centric and anterior occlusions. The excessive stresses in the TMJ of patients with mandibular asymmetry were associated with temporomandibular disorders.

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Photoelastic Analysis of Three-Dimensional Stress Systems using Scattered Light

Journal of the Royal Aeronautical Society ◽

10.1017/s0368393100104973 ◽

1940 ◽

Vol 44 (349) ◽

pp. 74-88 ◽

Cited By ~ 2

Author(s):

R. Weller ◽

J. K. Bussey

Keyword(s):

Elementary Theory ◽

Scattered Light ◽

Three Dimensional ◽

Plane Section ◽

Stress System ◽

Principal Stresses ◽

State Of Stress ◽

Polarised Light ◽

Photoelastic Analysis ◽

Good Agreement

SummaryA method has been developed for making photoelastic analyses of threedimensional stress systems by utilising the polarisation phenomena associated with the scattering of light. By this method, the maximum shear and the directions of the three principal stresses at any point within a model can be determined, and the two principal stresses at a free-bounding surface can be separately evaluated. Polarised light is projected into the model through a slit so that it illuminates a plane section. The light is continuously analysed along its path by scattering and the state of stress in the illuminated section is obtained. By means of a series of such sections, the entire stress field may be explored. The method was used to analyse the stress system of a simple beam in bending. The results were found to be in good agreement with those expected from elementary theory.

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A comparative study between zirconia and titanium abutments on the stress distribution in parafunctional loading: A 3D finite element analysis

Technology and Health Care ◽

10.3233/thc-202305 ◽

2020 ◽

Vol 28 (6) ◽

pp. 603-613 ◽

Cited By ~ 1

Author(s):

Efe Can Sivrikaya ◽

Mehmet Sami Guler ◽

Muhammed Latif Bekci

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Three Dimensional ◽

Von Mises Stress ◽

Principal Stresses ◽

Element Analysis ◽

Dimensional Finite Element ◽

3D Fea ◽

Von Mises ◽

Three Dimensional Finite Element

BACKGROUND: Zirconia has become a popular biomaterial in dental implant systems because of its biocompatible and aesthetic properties. However, this material is more fragile than titanium so its use is limited. OBJECTIVES: The aim of this study was to compare the stresses on morse taper implant systems under parafunctional loading in different abutment materials using three-dimensional finite element analysis (3D FEA). METHODS: Four different variations were modelled. The models were created according to abutment materials (zirconia or titanium) and loading (1000 MPa vertical or oblique on abutments). The placement of the implants (diameter, 5.0 × 15 mm) were mandibular right first molar. RESULTS: In zirconia abutment models, von Mises stress (VMS) values of implants and abutments were decreased. Maximum and minimum principal stresses and VMS values increased in oblique loading. VMS values were highest in the connection level of the conical abutments in all models. CONCLUSIONS: Using conical zirconia abutments decreases von Mises stress values in abutments and implants. However, these values may exceed the pathological limits in bruxism patients. Therefore, microfractures may be related to the level of the abutment.

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