scholarly journals Microdamage and Osteocyte-Lacuna Strain in Bone: A Microstructural Finite Element Analysis

1996 ◽  
Vol 118 (2) ◽  
pp. 240-246 ◽  
Author(s):  
P. J. Prendergast ◽  
R. Huiskes
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Remodeling ◽  
Damage Accumulation ◽  
Experimental Studies ◽  
Local Deformation ◽  
Element Analysis ◽  
Osteocyte Lacunae ◽  
Observed Damage ◽  
Living Tissues

Damage accumulation in living tissues occurs when the rate of damage formation is greater than the rate of damage repair. For very large increases in the loading rate of bones, this can result in “stress fractures” due to the growth and coalescence of fatigue related microdamage. At lower increases of loading rates, the damage accumulation process is halted because there is time for adaptive bone-remodeling to occur in response to the new load. However, it is not known if there is a relationship between microdamage and bone remodeling per se. One hypothesis for the control of bone remodeling is that osteocytes sense strains and mediate osteoblastic and osteoclastic activity. The purpose of this study was to investigate whether damage generates strains which may trigger bone remodeling. If this were true, then accumulative damage would cause adaptive bone remodeling. This study applies the methods of finite element analysis to determine the effect of observed damage mechanisms on the proposed sensors of remodeling in Haversian bone. Individual lamellae are modeled and osteocyte-lacunae are included in a generalized plane strain geometric representation. It is predicted that microdamage alters the local deformation behavior around lacunae, and that the changes increase as microdamage accumulates. Hence, if damage accumulates in a bone, it could be sensed as a change in strain at a microstructural level. The results give theoretical support to the experimental studies that have shown a correlation between microdamage and the initiation of resorption as a first step in bone remodeling.

Strength-based design of a sunflower stalk cutter machine design using finite element analysis and experimental validation

2021 ◽  
pp. 095440622110597
Author(s):  
Gürkan İrsel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Strain Gage ◽  
Experimental Validation ◽  
Experimental Studies ◽  
Fatigue Analysis ◽  
Structural Stress ◽  
Element Analysis ◽  
Strength Based

In this study, the total algorithm of the strength-based design of the system for mass production has been developed. The proposed algorithm, which includes numerical, analytical, and experimental studies, was implemented through a case study on the strength-based structural design and fatigue analysis of a tractor-mounted sunflower stalk cutting machine (SSCM). The proposed algorithm consists of a systematic engineering approach, material selection and testing, design of the mass criteria suitability, structural stress analysis, computer-aided engineering (CAE), prototype production, experimental validation studies, fatigue calculation based on an FE model and experimental studies (CAE-based fatigue analysis), and an optimization process aimed at minimum weight. Approximately 85% of the system was designed using standard commercially available cross-section beams and elements using the proposed algorithm. The prototype was produced, and an HBM data acquisition system was used to collect the strain gage output. The prototype produced was successful in terms of functionality. Two- and three-dimensional mixed models were used in the structural analysis solution. The structural stress analysis and experimental results with a strain gage were 94.48% compatible in this study. It was determined using nCode DesignLife software that fatigue damage did not occur in the system using the finite element analysis (FEA) and experimental data. The SSCM design adopted a multi-objective genetic algorithm (MOGA) methodology for optimization with ANSYS. With the optimization solved from 422 iterations, a maximum stress value of 57.65 MPa was determined, and a 97.72 kg material was saved compared to the prototype. This study provides a useful methodology for experimental and advanced CAE techniques, especially for further study on complex stress, strain, and fatigue analysis of new systematic designs desired to have an optimum weight to strength ratio.

The Finite-Element Analysis of Cylindrical Helical Tooth Milling Cutter Based on Marc

2011 ◽  
Vol 52-54 ◽  
pp. 1147-1152
Author(s):  
Guang Guo Zhang ◽  
Wei Jiang ◽  
Hong Hua Zhang ◽  
Huan Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cutting Forces ◽  
Element Model ◽  
Local Deformation ◽  
Analysis Software ◽  
Element Analysis ◽  
Milling Cutter ◽  
Cutter Life ◽  
The Finite Element Analysis

In the traditional designs of milling cutter, we cannot get the required accuracy of machining as there may be local deformation on the edges, even more the cutter can break down. Aiming at this situation, a finite-element model of straight pin milling cutter with helical tooth are built using Marc, a nonlinear finite-element analysis software, the different cutting forces of the milling cutter during the cutting process are analyzed and the cutting forces of the milling cutter at different parameters are studied. We get the stress, the strain and the temperature distribution of the milling cutter in different situation. Our work offer a theoretical basis of improving stress of the cutter, designing the structure of cutters reasonably and analyzing the cutter failure as well as a new method of analysis and calculation of the cutter life and strength.

Development of a Lower Extremity Model for Finite Element Analysis at Blast Condition

2011 ◽  
Author(s):  
Robbin Bertucci ◽  
Jun Liao ◽  
Lakiesha Williams
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shock Waves ◽  
Lower Extremity ◽  
Direct Contact ◽  
Computational Analysis ◽  
Experimental Studies ◽  
Lower Extremities ◽  
Element Analysis ◽  
Made In

Explosions are the leading cause of death on the battlefield [1]. These explosives generate shock waves which stimulate large accelerations and deformations. The resulting loads pose serious threats to military and civilians. Since lower extremities are in direct contact with the ground, the lower extremities are commonly injured during explosions [2]. These injuries could be seriously fatal. Although experimental studies have been performed to advance these understandings [2], limited progress has been made in computational analysis of shock waves on the lower extremity.

Experimental studies and finite-element analysis of the seismicity of north china plain

1982 ◽  
Vol 85 (1-2) ◽  
pp. 75-89 ◽  
Author(s):  
Huanyen Loo ◽  
Huizhen Song ◽  
Caihua Guo ◽  
Jianguo Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
North China Plain ◽  
North China ◽  
Experimental Studies ◽  
Element Analysis

Finite Element Analysis of Engine Bore Distortions During Boring Operation

1993 ◽  
Vol 115 (4) ◽  
pp. 379-384 ◽  
Author(s):  
N. N. Kakade ◽  
J. G. Chow
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Piston Ring ◽  
Experimental Studies ◽  
Temperature Gradients ◽  
Element Analysis ◽  
Temperature Changes ◽  
Simulation Procedure ◽  
Finite Element Package ◽  
Element Technique

Bore geometry is the major factor affecting oil comsumption, piston ring wear, and frictional losses in an engine. As such, auto industries have been constantly striving to develop better machining technologies to produce engine bores with greater precision. Experimental studies have shown that the bore distortion as a result of machining is mainly caused by temperatures and stresses created during cutting. Consequently, optimization of machining conditions so as to minimize both bore temperature gradients as well as mechanical stresses while machining should lead to the production of better bore geometry. This research develops a model aimed at simulating bore distortions caused by temperature changes and stresses generated during machining using finite element technique. The commercial finite element package ANSYS has been used along with the CAD package I-DEAS to simulate the boring process on DEC-VAX computers. The simulation procedure developed can be used to obtain a better understanding of the boring process, in particular, to determine distortion trends for different cutting conditions.

ANALYTICAL AND EXPERIMENTAL STUDIES ON 400 kV S/C PORTAL-TYPE GUYED TOWERS

2009 ◽  
Vol 09 (01) ◽  
pp. 85-106
Author(s):  
N. PRASAD RAO ◽  
S. J. MOHAN ◽  
R. P. ROKADE ◽  
R. BALA GOPAL
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Studies ◽  
Ground Level ◽  
Test Results ◽  
Element Analysis ◽  
Finite Element Software ◽  
The Finite Element Analysis ◽  
Guyed Towers ◽  
Analytical Behavior

The experimental and analytical behavior of 400 kV S/C portal-type guyed towers under different loading conditions is presented. The portal-type tower essentially consists of two masts extending outward in the transverse direction from the beam level to the ground. In addition, two sets of guys connected at the ground level project outward along the longitudinal axes and converge in the transverse axes. The experimental behavior of the guyed tower is compared with the results of finite element analysis. The 400 kV portal-type guyed towers with III and IVI type insulator strings are analyzed using finite element software. Full scale tower test results are verified through comparison with the results of the finite element analysis. The initial prestress in the guys is allowed to vary from 5% to 15% in the finite element modeling. The effect of prestress variation of the guys on the tower behavior is also studied.

3-D Non-Linear Finite Element Analysis of a Non-Gasketed Flange Joint Under Combined Internal Pressure and Axial Loading

2007 ◽  
Author(s):  
Muhammad Abid ◽  
Abdul W. Awan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Structural Integrity ◽  
Experimental Studies ◽  
Axial Loading ◽  
External Loading ◽  
Flange Joint ◽  
Element Analysis ◽  
Bolted Flange

A number of analytical and experimental studies have been conducted to study ‘strength’ and ‘sealing capability’ of bolted flange joint only under internal pressure loading. Due to the ignorance of the external i.e. axial loading, the optimized performance of the bolted flange joint can not be achieved. A very limited work is found in literature under combined internal pressure and axial loading. In addition, the present design codes do not address the effects of axial loading on the structural integrity and sealing ability of the flange joints. From previous studies, non-gasketed joint is claimed to have better performance as compared to conventional gasketed joint. To investigate non-gasketed joint’s performance i.e. joint strength and sealing capability under combined internal pressure and any applied external loading, an extensive 3D nonlinear finite element analysis is carried out and overall joint performance and behavior is discussed.

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