Fracture Analyses of Soft Materials With Hard Inclusion

2018 ◽  
Vol 85 (11) ◽  
Author(s):  
Pengyu Pei ◽  
Yan Shi ◽  
Guang Yang ◽  
Cunfa Gao
Keyword(s):  
Soft Materials ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Hard Inclusion ◽  
Applied Loading ◽  
Fracture Behaviors ◽  
Theoretical Predictions ◽  
Key Factor ◽  
Fracture Theory ◽  
Line Inclusion

This paper presents a detailed study on the fracture behaviors of soft materials with hard inclusion. Stress concentrations on the interfaces of hard and soft materials are considered as the key factor for structure fracture. Based on linear fracture theory, the fracture behaviors of soft materials with elliptical hard inclusion are investigated. Stress concentrations, consisting of tensile, hoop, and compressive stress, are observed with changes of inclusion geometries and the modulus ratio of hard and soft materials. And their influences on the categories of principal stress concentration are shown in a phase diagram in the current paper. Finite element analysis is carried out with consideration of the large deformation of soft material, which demonstrates the effectiveness of the theoretical predictions in a great scope of applied loading. Finally, the predictions based on theoretical and simulation results are validated by experiments. This work points out that the hard line inclusion is the source of danger in soft materials just like the crack in brittle materials.

Glulam rivet connections under eccentric loading

1987 ◽  
Vol 14 (5) ◽  
pp. 621-630 ◽  
Author(s):  
Erol Karacabeyli ◽  
Ricardo O. Foschi
Keyword(s):  
Failure Modes ◽  
Experimental Studies ◽  
Design Guidelines ◽  
Bearing Failure ◽  
Element Analysis ◽  
Theoretical Predictions ◽  
Failure Loads ◽  
Fracture Theory ◽  
Timber Engineering ◽  
Type Of Failure

Results from theoretical and experimental studies on the strength of glulam rivet connections under eccentric loading are presented. Two failure modes are studied: (1) rivet yielding in bending with simultaneous bearing failure of the wood under the rivet's shank and (2) wood failure around the rivet cluster. The latter is studied using brittle fracture theory and a finite element analysis of the stress distribution in the wood around the rivets.Experimental results are shown to compare well with theoretical predictions for failure loads and type of failure, and design guidelines are proposed. Key words: fasteners, wood connectors, glued-laminated, nails, timber engineering.

scholarly journals Modeling the Repair of a Crack in an HDPE Pipe

2021 ◽  
Vol 65 (2) ◽  
pp. 134-140
Author(s):  
Samira Liamani ◽  
Sahli Abderahmane
Keyword(s):  
Mechanical Characteristics ◽  
Horizontal Line ◽  
J Integral ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Applied Loading ◽  
Hdpe Pipe ◽  
Polymer Tubes ◽  
Gaseous Form ◽  
Loading Type

A pipe is a buried or aerial pipeline carrying goods, whether in liquid or gaseous form. Pipes are most often made from polymer tubes. These pipes prove to be subject to damage caused by a lack of material or crack thus calling for methods of repair or reinforcement.The objective of this study is to analyze by finite element analysis the presence of a horizontal crack in a high-density polyethylene pipe subjected to patch-corrected internal loading.Part of this study is devoted to analyzing the Von Misses stress distribution along a horizontal line, the applied loading type effect, the orientation of the fibers and the nature of the patch have been highlighted.The second part of our study is based on the calculation of the J-Integral where the same parameters of the first part were considered.The results clearly show that the mechanical characteristics of the composite must be optimized to provide an effective repair safely and allow relief of stress concentrations at the crack front.

A Preliminary Two-Dimensional Palpation Mechanics for Detecting a Hard Inclusion by Indentation of a Soft Matrix Under Large Strain

2019 ◽  
Vol 86 (5) ◽  
Author(s):  
Shengchen Liu ◽  
Kai-tak Wan
Keyword(s):  
Large Strain ◽  
Soft Materials ◽  
Finite Depth ◽  
Two Dimensional ◽  
Soft Layer ◽  
Element Analysis ◽  
Hard Inclusion ◽  
Soft Matrix ◽  
Indentation Axis ◽  
The Matrix

A rigid inclusion is embedded at a finite depth in a soft layer resting on a rigid substrate. A spherical indenter presses vertically onto the surface, deforming the matrix and displacing the inclusion. A subsurface inclusion initially near the indentation axis moves primarily downward, until an unstable lateral jump occurs to minimize the energy stored in the elastic medium. Such an instability is unique to soft materials undergoing large deformation. A two-dimensional plane-strain finite element analysis is used to simulate the 3D phenomenon.

Effective Convergence Checks for Verifying Finite Element Stresses at Three-Dimensional Stress Concentrations

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
J. R. Beisheim ◽  
G. B. Sinclair ◽  
P. J. Roache
Keyword(s):  
Finite Element ◽  
Error Estimation ◽  
A Posteriori Error Estimates ◽  
Three Dimensional ◽  
Posteriori Error ◽  
Test Problems ◽  
A Posteriori ◽  
Stress Concentrations ◽  
Element Analysis ◽  
A Posteriori Error

Current computational capabilities facilitate the application of finite element analysis (FEA) to three-dimensional geometries to determine peak stresses. The three-dimensional stress concentrations so quantified are useful in practice provided the discretization error attending their determination with finite elements has been sufficiently controlled. Here, we provide some convergence checks and companion a posteriori error estimates that can be used to verify such three-dimensional FEA, and thus enable engineers to control discretization errors. These checks are designed to promote conservative error estimation. They are applied to twelve three-dimensional test problems that have exact solutions for their peak stresses. Error levels in the FEA of these peak stresses are classified in accordance with: 1–5%, satisfactory; 1/5–1%, good; and <1/5%, excellent. The present convergence checks result in 111 error assessments for the test problems. For these 111, errors are assessed as being at the same level as true exact errors on 99 occasions, one level worse for the other 12. Hence, stress error estimation that is largely reasonably accurate (89%), and otherwise modestly conservative (11%).

Finite Element Analysis of Poor Distal Contact of the Femoral Component of a Cementless Hip Endoprosthesis

1993 ◽  
Vol 207 (4) ◽  
pp. 255-261 ◽  
Author(s):  
M Taylor ◽  
E W Abel
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Influencing Factor ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Element Analysis ◽  
Hip Endoprosthesis ◽  
Applied Loading ◽  
Femoral Geometry ◽  
Contact Models

The difficulty of achieving good distal contact between a cementless hip endoprosthesis and the femur is well established. This finite element study investigates the effect on the stress distribution within the femur due to varying lengths of distal gap. Three-dimensional anatomical models of two different sized femurs were generated, based upon computer tomograph scans of two cadaveric specimens. A further six models were derived from each original model, with distal gaps varying from 10 to 60 mm in length. The resulting stress distributions within these were compared to the uniform contact models. The extent to which femoral geometry was an influencing factor on the stress distribution within the bone was also studied. Lack of distal contact with the prosthesis was found not to affect the proximal stress distribution within the femur, for distal gap lengths of up to 60 mm. In the region of no distal contact, the stress within the femur was at normal physiological levels associated with the applied loading and boundary conditions. The femoral geometry was found to have little influence on the stress distribution within the cortical bone. Although localized variations were noted, both femurs exhibited the same general stress distribution pattern.

scholarly journals Evaluation of Different Restoration Combinations Used in the Reattachment of Fractured Teeth: A Finite Element Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Nagihan Guven ◽  
Ozgur Topuz ◽  
İhsan Yikilgan
Keyword(s):  
Finite Element Analysis ◽  
Glass Fiber ◽  
Composite Resin ◽  
Fracture Line ◽  
Core Material ◽  
Fiber Post ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Composite Resin Restoration ◽  
Glass Fiber Post

Objective. The purpose of this study was to test different restoration combinations used for constructing fractured endodontically treated incisors by reattaching their fractured fragments. Methods. Seven types of 3-D FEM mathematical root canal-filled models were generated, simulating cases of (OB) reattaching fractured fragments; (CrPL) reattaching fractured fragments + ceramic palatinal laminate; (CmPL) reattaching fractured fragments + composite palatinal laminate; (CM) reattaching fractured fragments + coronal 1/3 of the root was filled using core material; (BP) reattaching fractured fragments + glass fiber post; (CP) composite resin restoration + glass fiber post; and (OC) composite resin restoration. A 100-N static oblique force was applied to the simulated teeth with 135° on the node at 2 mm above the cingulum to analyze the stress distribution at the tooth. Results. For enamel tissue, the highest stress values were observed in model BP, and the lowest stress values were observed in model CmPL. For dentine tissue, the highest stress concentrations were observed around the fracture line for all models. Conclusions. Reattachment of fractured fragments by bonding may be preferred as a restoration option for endodontically treated incisors; also, palatinal laminate decreases the stress values at tooth tissues, especially at the enamel and the fracture line.

Practical Procedures for Technical and Economic Investigation of Ship Structural Details

1981 ◽  
Vol 18 (01) ◽  
pp. 51-68
Author(s):  
Donald Liu ◽  
Abram Bakker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Analysis Techniques ◽  
Structural Problems ◽  
Analysis Technique ◽  
The Finite Element Analysis ◽  
Structural Details

Local structural problems in ships are generally the result of stress concentrations in structural details. The intent of this paper is to show that costly repairs and lay-up time of a vessel can often be prevented, if these problem areas are recognized and investigated in the design stages. Such investigations can be performed for minimal labor and computer costs by using finite-element analysis techniques. Practical procedures for analyzing structural details are presented, including discussions of the results and the analysis costs expended. It is shown that the application of the finite-element analysis technique can be economically employed in the investigation of structural details.

Computer-Aided Gear Product Realization

2018 ◽  
Author(s):  
Alireza Yazdanshenas ◽  
Emilli Morrison ◽  
Chung-Hyun Goh ◽  
Janet K. Allen ◽  
Farrokh Mistree
Keyword(s):  
Computer Aided Design ◽  
Interaction Analysis ◽  
Gear Tooth ◽  
Integrated Design ◽  
System Level ◽  
Trial And Error ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Gear Design ◽  
Computer Aided

To save time and resources, many are making the transition to developing their ideas virtually. Computer-aided gear production realization is becoming more and more desired in the industry. To produce gears with custom qualities, such as material, weight and shape, the trial and error approach has yielded the best results. However, trial and error is costly and time consuming. The computer-aided integrated design and manufacturing approach is intended to resolve these drawbacks. A simple one stage reduction spur gearbox is used as an example in a case study. First, the gear geometry is developed using computer aided design (CAD) modeling. Next, using MATLAB/Simulink, the gear assembly is connected virtually to other subsystems for system expectations and interaction analysis. Finally, using finite element analysis (FEA) tools such as ABAQUS, a dynamic FEA of the gear integration is completed to analyze the stress concentrations and gear tooth failures. Through this method of virtual gear design, customized dimensions and specifications of gears for satisfying system-level requirements can be developed, thereby saving time and manufacturing costs for any custom gear design request.

Patient-Specific 3D Finite-Element Analysis of Miniscrew Implants During Orthodontic Treatment

2009 ◽  
Author(s):  
Hussein H. Ammar ◽  
Victor H. Mucino ◽  
Peter Ngan ◽  
Richard J. Crout ◽  
Osama M. Mukdadi
Keyword(s):  
Finite Element ◽  
Orthodontic Treatment ◽  
3D Model ◽  
Patient Specific ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Miniscrew Implants ◽  
Operative Planning ◽  
Miniscrew Implant ◽  
Maximum Stresses

Miniscrew implants have seen increasing clinical use as orthodontic anchorage devices with demonstrated stability. The focus of this study is to develop and simulate operative factors, such as load magnitudes and anchor locations to achieve desired motions in a patient-specific 3D model undergoing orthodontic treatment with miniscrew implant anchorage. A CT scan of a patient skull was imported into Mimics software (Materialise, 12.1). Segmentation operations were performed on the images to isolate the mandible, filter out noise, then reconstruct a smooth 3D model. A model of the left canine was reconstructed with the PDL modeled as a thin solid layer. A miniscrew was modeled with dimensions based on a clinical implant (BMK OAS-T1207) then inserted into the posterior mandible. All components were volumetrically meshed and optimized in Mimics software. Elements comprising the mandible bone and teeth were assigned a material based on their gray value ranges in HU from the original scan, and meshes were exported into ANSYS software. All materials were defined as linear and isotropic. A nonlinear PDL was also defined for comparison. For transverse forces applied on the miniscrew, maximum stresses increased linearly with loading and appeared at the neck or first thread and in the cortical bone. A distal tipping force was applied on the canine, and maximum stresses appeared in the tooth at the crown and apex and in the bone at the compression surface. Under maximum loading, stresses in bone were sufficient for resorption. The nonlinear PDL exhibited lower stresses and deflections than the linear model due to increasing stiffness. Numerous stress concentrations were seen in all models. Results of this study demonstrate the potential of patient-specific 3D reconstruction from CT scans and finite-element simulation as a versatile and effective pre-operative planning tool for orthodontists.

Elastic and elastic-plastic finite element analysis of hollow tubes with axisymmetric internal projections under combined axial and pressure loading

2001 ◽  
Vol 36 (4) ◽  
pp. 373-390 ◽  
Author(s):  
S. J Hardy ◽  
M. K Pipelzadeh ◽  
A. R Gowhari-Anaraki
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Plastic Material ◽  
Axial Loading ◽  
Material Model ◽  
Pressure Loading ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Applied Loading

This paper discusses the behaviour of hollow tubes with axisymmetric internal projections subjected to combined axial and internal pressure loading. Predictions from an extensive elastic and elastic-plastic finite element analysis are presented for a typical geometry and a range of loading combinations, using a simplified bilinear elastic-perfectly plastic material model. The axial loading case, previously analysed, is extended to cover the additional effect of internal pressure. All the predicted stress and strain data are found to depend on the applied loading conditions. The results are normalized with respect to material properties and can therefore be applied to geometrically similar components made from other materials, which can be represented by the same material models.

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