Evaluation of the Accuracy of Out-of-Plane Normal Stress Detection Using Novel Piezoresistive CMOS Sensors

2009 ◽  
Author(s):  
Benjamin Lemke ◽  
Rajashree Baskaran ◽  
Oliver Paul
Keyword(s):  
Normal Stress ◽  
Stress Component ◽  
Stress Detection ◽  
Free Surfaces ◽  
Plane Normal ◽  
Uncertainty Sources ◽  
Stress Components ◽  
Normal Stress Component ◽  
Out Of Plane ◽  
The Individual

This paper discusses the measurement opportunities arising from a novel piezoresistance sensor featuring vertical currents. Temperature-compensated measurements of a sum of the three normal stress components including the vertical normal stress, are presented. In specific applications with sensors located at free surfaces where the vertical normal stress component vanishes, a combination of this temperature-compensated measurement and a pseudo-Hall measurement yields the individual in-plane normal stresses. Furthermore, the temperature-uncompensated extraction of the vertical normal stress component is discussed with respect to the new measurement possibilities provided by the presented sensor. A sensitivity analysis illustrates the influence of individual uncertainty sources to the overall uncertainty of the measurement. Based on these results possible improvements in stress detection are suggested.

Non-Linear Two-Equation Model Taking Into Account the Wall-Limiting Behaviour and Redistribution of Stress Components

2003 ◽  
Author(s):  
Hirofumi Hattori ◽  
Yasutaka Nagano
Keyword(s):  
Normal Stress ◽  
Nonlinear Models ◽  
Stress Component ◽  
Equation Model ◽  
Normal Direction ◽  
Turbulence Energy ◽  
Proposed Model ◽  
Stress Components ◽  
Normal Stress Component ◽  
Limiting Behaviour

Nonlinear k–ε models have been extensively used in technological applications. It is clear from the assessment of the existing nonlinear k–ε models using DNS databases that the nonlinear models can not satisfy and reproduce exactly the wall-limiting behaviour and the anisotropy of Reynolds normal stress components. Especially, the Reynolds normal stress component, u22, in the wall-normal direction, which is proportional to x24 near the wall is not satisfied. Since the wall limiting behaviour of Reynolds normal stress components in the nonlinear model is determined by the turbulence energy k, which is proportional to x22 in the model, the Reynolds stress components, u12, u22 and u32 are proportional to x22. In this study, we have proposed a new nonlinear k–ε model which satisfies exactly the wall limiting behaviour of Reynolds normal stress components in the inertial and the noninertial frames. The proposed model can also predict well the anisotropy of the Reynolds normal stress components near the wall.

Representation of Three-Dimensional Stress Distributions by Mohr Circles

1955 ◽  
Vol 22 (2) ◽  
pp. 273-275
Author(s):  
G. A. Zizicas
Keyword(s):  
Normal Stress ◽  
Stress Component ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Shearing Stress ◽  
Principal Stresses ◽  
Normal Stress Component

Abstract O. Mohr has developed a diagram representing the normal stress component snn = σn and the total shearing stress component τn on an element of surface of any prescribed orientation with respect to the directions of the principal stresses. His procedure, however, does not give the orientation of the shearing stress τn within the element or, which is equivalent, the components of this shearing stress in a plane co-ordinate system within the element under consideration. An extension of the Mohr method that overcomes this limitation is presented in this note.

Piezoresistive CMOS sensor for out-of-plane normal stress

2012 ◽  
Vol 176 ◽  
pp. 10-18 ◽  
Author(s):  
Benjamin Lemke ◽  
Rajashree Baskaran ◽  
Oliver Paul
Keyword(s):  
Normal Stress ◽  
Plane Normal ◽  
Cmos Sensor ◽  
Out Of Plane

Contact Stress Analysis of Normally Loaded Rough Spheres

1962 ◽  
Vol 29 (3) ◽  
pp. 515-522 ◽  
Author(s):  
L. E. Goodman
Keyword(s):  
Shear Stress ◽  
Normal Stress ◽  
Contact Stress ◽  
Contact Region ◽  
Stress Component ◽  
Theory Of Elasticity ◽  
Relative Slip ◽  
Normal Stress Component ◽  
Incremental Formulation ◽  
Stress Functions

The Hertz analysis of contact stresses is extended to include the effects of friction on the interface between two elastic spheres compressed along the line connecting their centers. The problem is shown to be one of a class which requires incremental formulation. Stress functions of interest in connection with the analysis of the shear-loaded half-space in the linear theory of elasticity are developed. The distribution of shear stress needed to prevent relative slip of surficial points after they enter the contact region is found to be finite everywhere in the region. The ratio of this shear stress to the coexisting normal stress component is shown to exhibit a singularity at the edge of the contact region. This implies that when elastically dissimilar spheres are pressed together microscopic slip must occur in a narrow annulus at the boundary of the contact region.

X-ray measurement of triaxial residual stress on machined surfaces by the cosα method using a two-dimensional detector

2018 ◽  
Vol 51 (5) ◽  
pp. 1329-1338 ◽  
Author(s):  
Keisuke Tanaka
Keyword(s):  
Normal Stress ◽  
New Method ◽  
Shear Stresses ◽  
Plane Shear ◽  
X Ray ◽  
Plane Normal ◽  
Out Of Plane ◽  
Cutting Direction ◽  
Machined Surfaces

In recent years, the cosα method has attracted engineers as a new method of X-ray stress measurement using the whole Debye–Scherrer (D–S) ring recorded on a two-dimensional detector. The principle of the cosα method was first proposed by Taira, Tanaka & Yamasaki [J. Soc. Mater. Sci. Jpn, (1978),27, 251–256] for in-plane biaxial stress analysis and later extended by Sasaki and co-workers [Sasaki & Hirose (1995).Trans. Jpn Soc. Mech. Eng. Part A,61, 2288–2295; Sasaki, Takahashi, Sasaki & Kobayashi (2009).Trans. Jpn Soc. Mech. Eng. Part A,75, 219–227] to the triaxial state of stress. The method proposed by Sasaki and co-workers utilizes several D–S rings taken at different incident angles of X-rays in order to determine triaxial stresses. In the present paper, the cosα method was applied to measure triaxial residual stresses of uni-directionally machined surfaces of a carbon steel made by grinding, milling and planing. A recommended procedure for experimental measurements of in-plane normal and shear stresses and out-of-plane shear stress is proposed, together with a new method for determination of the out-of-plane normal stress. The tilt angle of X-ray incidence for stress determination is recommended to be larger than 35°, where the stress constant is low and the stress sensitivity is high. Normal incidence is recommended for the determination of out-of-plane shear stresses. The out-of-plane shear stress along the cutting direction was characteristic of uni-directionally machined surfaces and increased with cutting severity in the order of grinding, milling and planing. The in-plane normal stress was compressive for ground and milled surfaces, and the magnitude of compression was larger in the direction perpendicular to the cutting direction. On the basis of the stress values measured under different tilt angles, it is suggested that the magnitude of in-plane normal residual stress increases near the surface. The out-of-plane normal stress determined by the new method indicated a small compression.

scholarly journals A Lamination Model for Pressure-Assisted Sintering of Multilayered Porous Structures

2021 ◽  
Vol 5 (2) ◽  
pp. 53
Author(s):  
Zhi-He Jin ◽  
Corson L. Cramer
Keyword(s):  
Plate Theory ◽  
Applied Pressure ◽  
Porous Structures ◽  
Plane Normal ◽  
Sinter Forging ◽  
Sintering Time ◽  
Out Of Plane ◽  
Force Moment ◽  
The Individual ◽  
Time Required

This work describes a lamination model for pressure-assisted sintering of thin, multilayered, and porous structures based on the linear viscous constitutive theory of sintering and the classical laminated plate theory of continuum mechanics. A constant out-of-plane normal stress is assumed in the constitutive relation. The lamination relations between the force/moment resultants and the strain/curvature rates are presented. Numerical simulations were performed for a symmetric tri-layer laminate consisting of a 10% gadolinia doped ceria (Ce0.9Gd0.1O1.95-δ) composite structure, where porous layers were adhered to the top and bottom of a denser layer under uniaxially-applied pressures and the sinter forging conditions. The numerical results show that, compared with free sintering, the applied pressure can significantly reduce the sintering time required to achieve given layer thicknesses and porosities. Unlike free sintering, which results in a monotonic decrease of the laminate in-plane dimension, pressure-assisted sintering may produce an in-plane dimension increase or decrease, depending on the applied pressure and sintering time. Finally, the individual layers in the laminate exhibit different stress characteristics under pressure-assisted sintering.

Assessment of Pipeline Spiral Weld Cracks Subjected to Internal Pressure

2018 ◽  
Author(s):  
Mark C. Neuert ◽  
Thomas J. Dessein ◽  
Millan Sen
Keyword(s):  
Finite Element ◽  
Crack Length ◽  
Normal Stress ◽  
Extended Finite Element Method ◽  
Stress Component ◽  
General Tendency ◽  
Extended Finite Element ◽  
Pipe Axis ◽  
Propagation Behavior ◽  
Longitudinal Cracks

Spirally welded pipelines can make up significant portions of operator transmission systems, and may contain manufacturing anomalies that are susceptible to fatigue growth. Modifications to inputs of crack assessment models, such as CorLAS®, are required to account for the angle these cracks make with respect to the longitudinal pipe axis, given that these crack assessment models were developed for longitudinally orientated cracks. Two such modifications were investigated and are discussed in this paper. One approach considered the normal stress component perpendicular to the angled crack, for which a stress transformation calculator was developed. Another approach, adapted from API 579 and BS7910 standards, used an effective crack length calculated as the longitudinal projection of the full length of an angled crack. Failure pressures calculated using these approaches were compared to validated finite element (FE) results. For both modifications, the pressure capacity increased for angled cracks versus longitudinal cracks. The transformed normal stress approach resulted in non-conservative failure pressure predictions with respect to the FE models, whereas the modified crack length approach was conservative. Additionally, the extended finite element method (XFEM) was used to investigate the propagation behavior of angled cracks. It was found that the general tendency was for propagation parallel to the longitudinal pipe axis; however, when considering weld residual stresses, the crack propagation would be directed toward the direction of the spiral seam.

Deformation and Diffusion: Quantitative Relations

1993 ◽  
Author(s):  
Brian Bayly
Keyword(s):  
Normal Stress ◽  
Arc Length ◽  
Self Diffusion ◽  
Quantitative Form ◽  
Stress Components ◽  
And Diffusion ◽  
Pressure Driven

The purpose of this chapter is to put the ideas of Chapter 11 into quantitative form. The first step is to link L0 to N and K; L0 is the arc-length of the imaginary quarter-cylinders in Figure 11. 5b, N is the material's viscosity (Pa-sec), and K is its coefficient for pressure-driven self-diffusion (m2/Pa-sec). The point emphasized in Chapter 11 is that if two migration paths exist, one curved and one straight, but both having the same length and the same variation of normal-stress components along their length, migration will be equally vigorous along the two paths. Further, the shortening rates at the source-ends of the two paths will be equal. The procedure used to find the relation of L0 to (NK)1/2 is to write the two shortening rates and equate them.

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