Thermal Stress Analysis for Differential Pressure Sensors

2005 ◽  
Author(s):  
J. Albert Chiou ◽  
Steven Chen
Keyword(s):  
Thermal Stress ◽  
Thermal Stresses ◽  
Thermal Hysteresis ◽  
Pressure Sensors ◽  
Experimental Tests ◽  
Temperature Cycling ◽  
Finite Element Analyses ◽  
Sensing Element ◽  
Pressure Sensing ◽  
Temperature Environment

Pressure sensors should be capable of measuring pressure accurately and consistently without being disturbed by the temperature environment. With silicon’s better thermal material properties, silicon micormachined pressure sensors are mass-produced and widely used. However, a silicon pressure sensing element has to be packaged and protected. The thermal mismatching between the sensing element and packaging may generate stresses on the transducer of a sensing element and create thermal hysteresis and voltage shift during temperature cycling. The induced thermal stresses can easily deteriorate performance reliability. In this paper, finite element analyses and experimental tests were conducted to reduce the thermal stress and thermal hysteresis. With the glass substrate to isolate the stress from plastic housing, the thermal hysteresis can be significantly improved. The die placement and dispense pattern can be also optimized to further improve the thermal hysteresis.

CMOS-MEMS Based Current Mirror MOSFET Embedded Pressure Sensor for Healthcare and Biomedical Applications

2013 ◽  
Vol 647 ◽  
pp. 315-320 ◽  
Author(s):  
Pradeep Kumar Rathore ◽  
Brishbhan Singh Panwar
Keyword(s):  
Pressure Sensor ◽  
Biomedical Applications ◽  
Circuit Simulation ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Cmos Technology ◽  
Current Mirror ◽  
Sensing Element ◽  
Pressure Sensing ◽  
Cmos Mems

This paper reports on the design and optimization of current mirror MOSFET embedded pressure sensor. A current mirror circuit with an output current of 1 mA integrated with a pressure sensing n-channel MOSFET has been designed using standard 5 µm CMOS technology. The channel region of the pressure sensing MOSFET forms the flexible diaphragm as well as the strain sensing element. The piezoresistive effect in MOSFET has been exploited for the calculation of strain induced carrier mobility variation. The output transistor of the current mirror forms the active pressure sensing MOSFET which produces a change in its drain current as a result of altered channel mobility under externally applied pressure. COMSOL Multiphysics is utilized for the simulation of pressure sensing structure and Tspice is employed to evaluate the characteristics of the current mirror pressure sensing circuit. Simulation results show that the pressure sensor has a sensitivity of 10.01 mV/MPa. The sensing structure has been optimized through simulation for enhancing the sensor sensitivity to 276.65 mV/MPa. These CMOS-MEMS based pressure sensors integrated with signal processing circuitry on the same chip can be used for healthcare and biomedical applications.

scholarly journals Experimental Investigation of Electro-thermal Stress Impact on SiC-BJTs Electrical Characteristics

2013 ◽  
Vol 2013 (HITEN) ◽  
pp. 000290-000297
Author(s):  
Thibaut Chailloux ◽  
Cyril Calvez ◽  
Pascal Bevilacqua ◽  
Dominique Planson ◽  
Dominique Tournier
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Room Temperature ◽  
Thermal Stresses ◽  
Temperature Cycling ◽  
Bipolar Junction Transistors ◽  
Electrical Characteristics ◽  
Switching Operation ◽  
Operation Temperature ◽  
The Stability

The aim of this study consists in investigating the effects of electrical and thermal stresses on SiC n-p-n bipolar junction transistors (BJTs). The stability of the electrical characteristics of BJTs is inspected under switching operation, DC operation, temperature cycling and continuous thermal stress up to 225°C. While switching operation and temperature cycling for several hours lead to significant changes at 25°C, the electrical characteristics were little degraded at high temperature. Besides, DC operation and continuous thermal stress did not result in significant degradation at all, both at room temperature and at high temperature.

scholarly journals Investigation of the effect of thermal stress on the interface damage of hybrid biocomposite materials

2019 ◽  
Vol 23 (1) ◽  
pp. 253-258
Author(s):  
Salima Sadat ◽  
Allel Mokaddem ◽  
Bendouma Doumi ◽  
Mohamed Berber ◽  
Ahmed Boutaous
Keyword(s):  
Thermal Stress ◽  
Thermal Stresses ◽  
Natural Fibers ◽  
Experimental Tests ◽  
Genetic Modeling ◽  
Axial Tensile ◽  
Acoustic Technique ◽  
Nonlinear Acoustic ◽  
Applied Stresses ◽  
Hybrid Biocomposite

Abstract In this paper, we have studied the effect of thermal stress on the damage of fiber-matrix interface of a hybrid biocomposite composed of two natural fibers, Hemp, Sisal, and Starch matrix. Our genetic modeling used the nonlinear acoustic technique based on Cox’s analytical model, Weibull’s probabilistic model, and Lebrun’s model describing the thermal stress by the two coefficients of expansion. The stress applied to our representative elementary volume is a uni-axial tensile stress. The numerical simulation shows that the Hemp- Sisal/Starch hybrid biocomposite is most resistant to thermal stresses as compared with Hemp/Starch biocomposite. It also shows that hybrid biocomposite materials have a high resistance to applied stresses (mechanical and thermal) compared to traditional materials and biocomposite materials. The results obtained in our study coincide perfectly with the results of Antoine et al., which showed through experimental tests that natural fibers perfectly improve the mechanical properties of biocomposite materials.

scholarly journals Control of Thermophysical Properties of Langasite-Type La3Ta0.5Ga5.5O14 Crystals for Pressure Sensors

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 936
Author(s):  
Haruki Usui ◽  
Makoto Tokuda ◽  
Kazumasa Sugiyama ◽  
Takuya Hoshina ◽  
Takaaki Tsurumi ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Temperatures ◽  
Thermal Stresses ◽  
Pressure Sensors ◽  
Czochralski Method ◽  
Order Type ◽  
Cation Site ◽  
Young’S Moduli ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

We present a possible method to reduce the anisotropy of the thermal stress generated on langasite-type La3Ta0.5Ga5.5O14 (LTG) piezoelectric crystals arising from the mismatch of the thermal expansion coefficients and Young’s moduli of the crystals and metals at high temperatures. To formulate this method, the thermal stresses of order-type langasite crystals, in which each cation site is occupied by one element only, were calculated and compared to each other. Our results suggest that the largest cation site affects the thermal stress. We attempted to replace La3+ in LTG by a larger ion and considered Sr2+. Single crystals of strontium-substituted LTG (Sr-LTG) were grown using the Czochralski method. The thermal stress along the crystallographic c-axis decreased but that perpendicular to the c-axis increased by strontium substitution into the LTG crystal. The anisotropic thermal stress was reduced effectively. The Sr-LTG single crystal is a superior candidate material for pressure sensors usable at high temperatures.

Thermal Hysteresis Analysis of MEMS Pressure Sensors

2004 ◽  
Author(s):  
J. Albert Chiou ◽  
Steven Chen
Keyword(s):  
Thermal Hysteresis ◽  
Pressure Sensors ◽  
Phenomenological Theory ◽  
Sensing Element ◽  
Element Analysis ◽  
Development Cycle ◽  
The Finite Element Analysis ◽  
Sensor Signals ◽  
Temperature Levels ◽  
Mems Pressure Sensors

Thermal hysteresis reduction is usually a difficult task to tackle for micromachined pressure sensors especially when shrinking the piezoresistive transducer (PRT) sensing element. Since thermal hysteresis involves the entire thermal cycling history and complicated material properties varied with temperatures, viscoplastic deformation makes the problem very complicated when dealing with high-precision sensor signals. The approach to simplify and quickly resolve the thermal hysteresis problem is the key methodology proposed by this paper. The objective of this project is to optimize the metal layout design on the sensing element and lower down the thermal hysteresis. It is time consuming and cost ineffective to rely purely on the hardware tests to solve the thermal hysteresis problem. ANSYS is used to predict the shear stress at the transducer location and the phenomenological theory of silicon piezoresistance is used to calculate the output voltage and thermal hysteresis. The element-death-and-birth technique is used to simulate the bonding process at various temperature levels for the sensing element packaging. With the aid of the finite element analysis (FEA) tool, the PRT sensing element design was quickly optimized and product development cycle time was reduced.

Ultrasensitive, flexible, and low-cost nanoporous piezoresistive composites for tactile pressure sensing

Nanoscale ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 2779-2786 ◽  
Author(s):  
Jing Li ◽  
Santiago Orrego ◽  
Junjie Pan ◽  
Peisheng He ◽  
Sung Hoon Kang
Keyword(s):  
Carbon Nanotube ◽  
Polymer Composites ◽  
Low Cost ◽  
Pressure Sensors ◽  
Nanoporous Carbon ◽  
Pressure Sensing ◽  
Etching Method ◽  
Piezoresistive Pressure Sensors

We report a facile sacrificial casting–etching method to synthesize nanoporous carbon nanotube/polymer composites for ultra-sensitive and low-cost piezoresistive pressure sensors.

Flexible pressure sensing film based on ultra-sensitive SWCNT/PDMS spheres for monitoring human pulse signals

2015 ◽  
Vol 3 (27) ◽  
pp. 5436-5441 ◽  
Author(s):  
Yan-Long Tai ◽  
Zhen-Guo Yang
Keyword(s):  
Pressure Sensors ◽  
Pressure Sensing ◽  
Prosthetic Limbs ◽  
Electronic Skin ◽  
Essential Components ◽  
Biomedical Diagnostics ◽  
Healthcare Monitoring ◽  
Flexible Pressure Sensors ◽  
Human Healthcare

Flexible pressure sensors are essential components of an electronic skin for future attractive applications ranging from human healthcare monitoring to biomedical diagnostics to robotic skins to prosthetic limbs.

Three Turnaround Heat Treating Studies

2003 ◽  
Author(s):  
Jaan Taagepera ◽  
Marty Clift ◽  
D. Mike DeHart ◽  
Keneth Marden
Keyword(s):  
Heat Treatment ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Heat Treating ◽  
Element Analysis ◽  
Stress Profiles ◽  
Insight Into

Three vessel modifications requiring heat treatment were analyzed prior to and during a planned turnaround at a refinery. One was a thick nozzle that required weld build up. This nozzle had been in hydrogen service and required bake-out to reduce the potential for cracking during the weld build up. Finite element analysis was used to study the thermal stresses involved in the bake-out. Another heat treatment studied was a PWHT of a nozzle replacement. The heat treatment band and temperature were varied with location in order to minimize cost and reduction in remaining strength of the vessel. Again, FEA was used to provide insight into the thermal stress profiles during heat treatment. The fmal heat treatment study was for inserting a new nozzle in a 1-1/4Cr-1/2Mo reactor. While this material would ordinarily require PWHT, the alteration was proposed to be installed without PWHT. Though accepted by the Jurisdiction, this nozzle installation was ultimately cancelled.

Steady-State Thermal Stresses in Wedge-Shaped Cutting Tools

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Equivalent Stress ◽  
Cutting Tools ◽  
Thermoelastic Stress ◽  
Plastic State ◽  
Steady State Heat

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.

Sign in / Sign up

Export Citation Format

Share Document