A Parallel three-dimensional elasto-plastic finite element analysis in a workstation cluster environment

Three-dimensional finite element analysis of cold expansion of adjacent holes

Assessment of the interaction of corrosion defects on steel pipelines under combined internal pressure and longitudinal compression using finite element analysis

Assessment of three-dimensional crack growth in ductile layered material systems

In this paper, three-dimensional elasto-plastic finite element analysis was performed on flexible pavements under vertical repeated traffic loads to evaluate their shakedown behavior. Six different pavements with different structural number (SN) were modeled and subjected to a wide range of cyclic vehicle loads. Shakedown limits were obtained considering both failure and serviceability restraints. Results indicate that shakedown coefficient and shakedown bearing capacity increase with a rise in SN for all load types. Lower limit of shakedown bearing capacity versus SN can be regarded as a criterion for pavement design. Besides, shakedown failure-displacement factor (SFDF) was introduced as an index which is able to include both failure and serviceability criteria to compare pavements in terms of their shakedown behavior. Results suggest increase in SFDF with increasing SN, particularly for light loads. Furthermore, results indicate that increase in asphalt layer thickness always improves shakedown bearing capacity, while increase in base and subbase layer thickness is not only ineffective beyond an effective thickness but may also be damaging. In addition, the results of the present study were compared to lower bound and upper bound shakedown analysis for verification and showed reasonable agreement.

Residual thermal strains and stresses in nickel aluminide matrix composites

Nonlinear subgrade modulus of sandy soils for analysis of piled raft foundations

The purpose of this study was to investigate the effects of composite resin restorations on the stress distribution of notch shaped noncarious cervical lesion using three-dimensional (3D) finite element analysis (FEA). Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072 ; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). ANSYS (Swanson Analysis Systems, Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid or flowable resin and each restoration was simulated with adhesive layer thickness () A static load of 500 N was applied on a point load condition at buccal cusp (loading A) and palatal cusp (loading B). The principal stresses in the lesion apex (internal line angle of cavity) and middle vertical wall were analyzed using ANSYS. The results were as follows 1. Under loading A, compressive stress is created in the unrestored and restored cavity. Under loading B, tensile stress is created. And the peak stress concentration is seen at near mesial corner of the cavity under each load condition. 2. Compared to the unrestored cavity, the principal stresses at the cemeto-enamel junction (CEJ) and internal line angle of the cavity were more reduced in the restored cavity on both load con ditions. 3. In teeth restored with hybrid composite, the principal stresses at the CEJ and internal line angle of the cavity were more reduced than flowable resin.

Comparison of the biomechanical behavior of different fixation configurations following Le Fort I advancement and inferior repositioning surgery: A three-dimensional finite element analysis.

Comparison of five different fixation techniques of sagittal split ramus osteotomy using three-dimensional finite elements analysis

This paper deals with a three-dimensional stress analysis for link chains subjected to tensile loads. The analysis was done using the finite-element method to examine the strength of the link chains. The effects of the dimensions of link chains on Misess's stress at the border between the curved part and the straight part in the link, and at the outer part, of which the inner part contacted with the inner part of the other link, were shown through numerical calculations. For verification, photoelastic experiments and measurement of strain were performed. The analytical results were in fairly good agreement with the experimental results. It was clarified that the strength of link chains can be improved by optimizing the link pitch, the link width, shape of the link section and compressed depth. Discussion is also presented on the estimation of the strength of the link chain subjected to tensile loads.

Objective To evaluate the effects of femoral offset (FO) on the stress level of bone cement total hip arthroplasty (THA) in the elder patients by the three-dimensional finite element analysis. Methods The normal bilateral hip joints in two cases was determined with CT imaging,with parameters including FO,neck shaft angle and neck length.The three-dimensional finite element model of THA was built so as to make Von Mises stress analysis of the changes of different neck lengths,neck shaft angles and FO. Results Stress levels in the prosthesis and bone cement reduced monotonically with the increase of neck shaft angles.In the meantime,the stress levels were lowered when neck length was in a range of 35-44 mm,but beyond the range they showed monotonous increase. Conclusions The reduction of stress levels of prosthesis and bone cement,promotion of femur stress and extension of range of motion of hip joints are closely related to FO.FO reconstruction benefits the restoration of abductor force arm and biomechanical function of normal hip joints. Key words: Femur; Arthroplasty,replacement,hip; Finite element analysis; Offset

Parallel processing, neural networks and genetic algorithms

Full-scale field tests were conducted on two 8.5-m (28-ft) span reinforced concrete arch culverts. The culverts were subjected to service live loads at depths of cover from 0.3 to 0.9 m (1 to 3 ft). At 1 ft of fill, the culverts were loaded with a simulated single-axle live load greater than 980 kN (220,000 lb). Field data collected included arch deflection, interface pressure, concrete strain, and reinforcing strain. The computer modeling of the live-load tests is reported. Two- and three-dimensional finiteelement analyses were conducted. Nonlinear material models were used for the backfill soil and the reinforced concrete in both the two- and three-dimensional analyses. Results from the finite-element analyses are compared with the field test data. Results of this study indicate that the two-dimensional models are limited in their ability to predict the longitudinal spreading of live load forces in the culverts and to predict maximum moments larger than those in the actual structure. The three-dimensional finite-element deflection predictions were dependent on the properties used to define the concrete material model; however, the design forces (moment, thrust, and shear) did not show the same sensitivity. This indicates that for typical structural design, material parameters may be approximated without seriously degrading the accuracy of predicted design forces. The test structures met AASHTO design criteria for strength and serviceability.

Purpose To investigate effects of number and location on patterns of von Mises stress distribution and volume average stress on abutment tooth, edentulous ridge, mini dental implant, and surrounding bone of mini dental implant-assisted mandibular Kennedy class I removable partial denture. Materials and Methods Eight three-dimensional finite element models of mandibular Kennedy class I with different numbers and locations of mini dental implants were constructed. Mini dental implants were generated in the area of second premolar, first molar, and second molar, respectively. A static load of 400 N was applied on all models. The von Mises stress and volumetric average stress were calculated by three-dimensional finite element analysis. Result The minimum volumetric average stress of abutment tooth was found in the model, where there was one mini dental implant at the second molar position and 2 mini dental implants at first molar and second molar positions. The model with three mini dental implants had reduced volumetric average stress of abutment tooth, which was not different from the model with two mini dental implants. However, the minimum volumetric average stress of mini dental implant and surrounding bone were found when three mini dental implants were applied, followed by two and one mini dental implants, respectively. Conclusion Placing at least one mini dental implant at a second molar position can help reduce stress transferred to the abutment tooth. Stresses around each implant and surrounding bone reduced with increased numbers of mini dental implants.

Clarification of the protocol for using short implants is required to enable widespread use of short implants as an available treatment option. The purpose of this study was to investigate the influences of implant length and diameter, bicortical anchorage, and sinus augmentation on peri-implant cortical bone stress by three-dimensional finite element analysis. For bone models with bone quantity A and C in the maxillary molar region, three-dimensional finite element analysis was performed using different lengths and diameters of implant computer-aided design models, and the degree of maximum principal stress distribution for each model was calculated. For bone quantity A models, the degree of stress distribution of the 4-mm-diameter, 6-mm-length implant was the greatest. For bone quantity C models, the degree of stress distribution of the 5-mm-diameter, 6-mm-length implant with bicortical anchorage was much smaller than that for the 4-mm-diameter, 13-mm-length implant with sinus augmentation. The results of this study suggest that 6-mm-length implants should be selected in cases with bone quantity C where the bone width permits increasing implant diameter from 4 mm to 5 mm.