scholarly journals Tests for equivalence of the stress state and the generalized stress-strain diagram babbitt Tin-based.

2014 ◽  
Vol 2014 (3) ◽  
pp. 26-34 ◽  
Author(s):  
Михаил Зернин ◽  
Mikhail Zernin
Keyword(s):  
Stress State ◽  
Experimental Investigations ◽  
Stress And Strain ◽  
Strain Diagram ◽  
Stress Strain ◽  
Different Types

Describes the methodologies and results of experimental investigations on the basis of tin babbitt in different types of stress. Specification of parameters of the criterion of equivalence of states of stress and strain diagram obtained single babbitt.

Laminated Composite Hypar Shells as Roofing Units

2018 ◽  
pp. 249-269
Author(s):  
Sarmila Sahoo
Keyword(s):  
Boundary Conditions ◽  
Strain State ◽  
Laminated Composite ◽  
Experimental Investigations ◽  
Stress Strain ◽  
Bending Vibration ◽  
Broad Perspective ◽  
Stiffened Shells ◽  
Various Boundary Conditions ◽  
Different Types

This chapter presents a broad perspective of the recent research done on laminated composite hypar shells used as roofing units. Different types of analysis including bending, vibration, buckling, impact, and failure are included. The chapter is collated and categorized based on various aspect of research. The first aspect concentrates on typical analyses including problems in which various boundary conditions and laminations are considered. Then it focuses on the structural complexities which include stiffened shells, shells with cutouts, etc. The basic results of theoretical and experimental investigations of stress-strain state, vibration, buckling, and failure are summarized in this chapter incorporating the review of materials published in scientific and technical journals and proceedings in recent times.

scholarly journals Infarcted Left Ventricles Have Stiffer Material Properties and Lower Stiffness Variation: Three-Dimensional Echo-Based Modeling to Quantify In Vivo Ventricle Material Properties

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Longling Fan ◽  
Jing Yao ◽  
Chun Yang ◽  
Dalin Tang ◽  
Di Xu
Keyword(s):  
Wall Thickness ◽  
Material Properties ◽  
Strain Curve ◽  
Stress And Strain ◽  
Stress Strain ◽  
Material Stiffness ◽  
The Mean ◽  
Lv Volume ◽  
Parameter Values

Methods to quantify ventricle material properties noninvasively using in vivo data are of great important in clinical applications. An ultrasound echo-based computational modeling approach was proposed to quantify left ventricle (LV) material properties, curvature, and stress/strain conditions and find differences between normal LV and LV with infarct. Echo image data were acquired from five patients with myocardial infarction (I-Group) and five healthy volunteers as control (H-Group). Finite element models were constructed to obtain ventricle stress and strain conditions. Material stiffening and softening were used to model ventricle active contraction and relaxation. Systolic and diastolic material parameter values were obtained by adjusting the models to match echo volume data. Young's modulus (YM) value was obtained for each material stress–strain curve for easy comparison. LV wall thickness, circumferential and longitudinal curvatures (C- and L-curvature), material parameter values, and stress/strain values were recorded for analysis. Using the mean value of H-Group as the base value, at end-diastole, I-Group mean YM value for the fiber direction stress–strain curve was 54% stiffer than that of H-Group (136.24 kPa versus 88.68 kPa). At end-systole, the mean YM values from the two groups were similar (175.84 kPa versus 200.2 kPa). More interestingly, H-Group end-systole mean YM was 126% higher that its end-diastole value, while I-Group end-systole mean YM was only 29% higher that its end-diastole value. This indicated that H-Group had much greater systole–diastole material stiffness variations. At beginning-of-ejection (BE), LV ejection fraction (LVEF) showed positive correlation with C-curvature, stress, and strain, and negative correlation with LV volume, respectively. At beginning-of-filling (BF), LVEF showed positive correlation with C-curvature and strain, but negative correlation with stress and LV volume, respectively. Using averaged values of two groups at BE, I-Group stress, strain, and wall thickness were 32%, 29%, and 18% lower (thinner), respectively, compared to those of H-Group. L-curvature from I-Group was 61% higher than that from H-Group. Difference in C-curvature between the two groups was not statistically significant. Our results indicated that our modeling approach has the potential to determine in vivo ventricle material properties, which in turn could lead to methods to infer presence of infarct from LV contractibility and material stiffness variations. Quantitative differences in LV volume, curvatures, stress, strain, and wall thickness between the two groups were provided.

Theoretical and experimental investigations of the stress state of elastic cylinders with grooves

1983 ◽  
Vol 19 (10) ◽  
pp. 862-866
Author(s):  
Yu. N. Nemish ◽  
Yu. I. Vologzhaninov ◽  
A. I. Zirka ◽  
N. M. Bloshko
Keyword(s):  
Stress State ◽  
Experimental Investigations ◽  
Elastic Cylinders

Random Loads Fatigue: The Use of Spectral Methods Within Multibody Simulation

2005 ◽  
Author(s):  
Claudio Braccesi ◽  
Filippo Cianetti ◽  
Luca Landi
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Dynamic Simulation ◽  
Fatigue Damage ◽  
Spectral Methods ◽  
Mechanical Systems ◽  
Frequency Domain Method ◽  
Stress And Strain ◽  
Damage Evaluation ◽  
Multibody Dynamic

The evaluation of the fatigue damage performed by using the Power Spectral Density function (PSD) of stress and strain state is proving to be extremely accurate for a family of random processes characterized by the property of being stationary. The present work’s original contribution is the definition of a methodology which extracts stress and strain PSD matrices from components modelled using a modal approach (starting from a finite element modelling and analysis) within mechanical systems modelled using multibody dynamic simulation and subject to a generic random load (i.e. multiple-input, with partially correlated inputs). This capability extends the actual stress evaluation scenario (principally characterised by the use of finite element analysis approach) to the multibody dynamic simulation environment, more powerful and useful to simulate complex mechanical systems (i.e. railway, automotive, aircraft and aerospace systems). As regards the fatigue damage evaluation, a synthesis approach to evaluate an equivalent stress state expressed in terms of the PSD function of Preumont’s “equivalent von Mises stress (EVMS)”, starting from the complete stress state representation expressed in terms of PSD stress matrix and easily usable in the consolidated spectral methods, is proposed. This approach allows and has allowed the use of the above methods such as the Dirlik formula as a damage evaluation method. An additional result is the conception and implementation of a frequency domain method for the component’s most probable state of stress, allowing quickly identification of the most stressed and damageble locations. The described methodologies were developed and embedded into commercial simulation codes and verified by using as a test case a simple reference multibody model with a simple flexible component.

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