scholarly journals First steps to develop a sensor for a Tian–Calvet calorimeter with increased sensitivity

2016 ◽  
Vol 5 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Franz Schubert ◽  
Michael Gollner ◽  
Jaroslaw Kita ◽  
Florian Linseis ◽  
Ralf Moos
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Time Constant ◽  
Room Temperature ◽  
Starting Point ◽  
Layer Technique ◽  
Increased Sensitivity ◽  
Low Mass ◽  
Good Starting Point ◽  
Calvet Calorimeter

Abstract. Initial steps to apply a ceramic multi-layer technique to build a new sensor for a Tian–Calvet calorimeter are presented in this contribution. The new sensor has a stacked design of ceramic sensor discs and insulating rings. The development was finite-element method (FEM) supported to design the sensor disc. In the next step, the function of the sensor disc was proven up to a temperature of 600 °C. Finally, the entire stack was tested at room temperature, delivering a resolution of 5 µW and a maximum sensitivity of 8.5 µV mW−1. The time constant is strongly dependent on the mass of the cuvette. We show that the time constant of the sensor can be more exactly characterized when using a novel low temperature co-fired ceramic (LTCC) cuvette with a low mass and an integrated heater. Then, the time constant can be reduced to T1∕e = 118 s. The new sensor shows similar specifications as commercial devices and presents a good starting point for future high temperature applications.

Numeric Analysis for Resonant Frequency of Rotating Blade

2009 ◽  
Vol 16-19 ◽  
pp. 1365-1369
Author(s):  
Di Zhao ◽  
Ke Qin Ding ◽  
Xin Chun Shang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Vibration ◽  
Resonant Frequency ◽  
Room Temperature ◽  
Vibration Characteristics ◽  
Resonance Analysis ◽  
Working Temperature ◽  
Rotating Blade ◽  
Dynamic Frequency

The paper implements numeric computation to analyze free vibration characteristics of rotating blade by the means of finite element method. The effects of rotate speed and temperature on the resonant frequency of blades are considered. The static frequency and the dynamic frequency under working speed for the room temperature and working temperature are calculated, and the various modes are obtained. The resonance analysis is given by Campbell graph in which shows the distribution of resonant points for resonant frequency and rotate speed under the different excitation.

An Investigation of the Shell Nosing Process by the Finite-Element Method. Part 1: Nosing at Room Temperature (Cold Nosing)

1982 ◽  
Vol 104 (3) ◽  
pp. 305-311 ◽  
Author(s):  
Ming-Ching Tang ◽  
Shiro Kobayashi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Room Temperature ◽  
Moving Boundary ◽  
Thickness Distribution ◽  
The Finite Element Method ◽  
Forming Process ◽  
Finite Element Program ◽  
Strain Rate Effects ◽  
Element Method

The metal-forming process of shell nosing at room temperature was analyzed by the finite-element method. The strain-rate effects on materials properties were included in the analysis. In cold nosing simulations, the nine-node quadrilateral elements with quadratic velocity distribution were used for the workpiece. The treatment of a moving boundary in the analysis of nosing is discussed and successfully implemented in the finite-element program. FEM simulations of 105-mm dia. shells of AISI 1018 steel and aluminum 2024 were performed and solutions were obtained in terms of load-displacement curves, thickness distribution, elongation, and strain distributions. Comparisons with experimental data show very good agreement.

scholarly journals Optimization of a sensor for a Tian–Calvet calorimeter with LTCC-based sensor discs

2016 ◽  
Vol 5 (2) ◽  
pp. 381-388
Author(s):  
Franz Schubert ◽  
Michael Gollner ◽  
Jaroslaw Kita ◽  
Florian Linseis ◽  
Ralf Moos
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Low Temperature ◽  
Maximum Deviation ◽  
Sensor Design ◽  
Fem Model ◽  
Basic Part ◽  
Melting Temperatures ◽  
Better Than ◽  
Calvet Calorimeter

Abstract. In this work, it is shown how a finite element method (FEM) model of a Tian–Calvet calorimeter is used to find improvements in the sensor design to increase the sensitivity of the calorimeter. By changing the layout of the basic part of the sensor, which is a low temperature co-fired ceramics (LTCC) based sensor disc, an improvement by a factor of 3 was achieved. The model was validated and the sensors were calibrated with a set of measurements that were later used to determine the melting enthalpies and melting temperatures of indium and tin samples. Melting temperatures showed a maximum deviation of 0.2 K while the enthalpy was measured with a precision better than 1 % for most samples. The values for tin deviate by less than 2 % from literature data.

scholarly journals Evaluation of Normal Pressures during Filling in Steel Hoppers with Eccentric Outlet

2020 ◽  
Vol 9 (3) ◽  
pp. 138-149
Author(s):  
Alireza Moazezi Mehretehran ◽  
Shervin Maleki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Physical Space ◽  
Industrial Applications ◽  
Filling Process ◽  
Material Parameters ◽  
Starting Point ◽  
Shallow Side ◽  
Two Parameters ◽  
Complicated Geometries

Filling pressures are a necessary starting point in the design of silos and hoppers. The hoppers with complicated geometries are common in industrial applications due to physical space constraints and the need to interface with other processing equipment. The current paper deals with the effect of outlet eccentricity on normal pressures formed in steel hoppers during distributed filling process. Using finite element method, progressive filling process in hoppers was simulated and by changing the percentage of outlet eccentricity, the variation of pressure distribution was fully studied. The results showed an increase in the normal pressures of shallow side compared with the steep side of eccentric hopper. To quantify the pressure asymmetry, two parameters were introduced and they were evaluated for practical range of material parameters and steel hoppers dimensions. The results obtained are of interest since they facilitate the design of silos and hoppers with eccentric outlet.

Coupling Finite Element Method and Perturbation Techniques for Non Linear Vibrations of Plates

1999 ◽  
Author(s):  
L. Azrar ◽  
R. Benamar ◽  
M. Potier-Ferry
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computation Time ◽  
Free Vibrations ◽  
Perturbation Techniques ◽  
Structural Problems ◽  
Starting Point ◽  
Linear Vibrations ◽  
The Right ◽  
Element Method

Abstract The effectiveness of the coupling of the perturbation techniques and the finite element method has been demonstrated using a method called Asymptotic-Numerical Method (ANM). This concept eliminates the major difficulties of the classical perturbation methods namely the complexity of the right hand sides and the limitation of the validity of the solution obtained. In this paper we present the development of this method and its applicability for large amplitudes free vibrations of plates. The displacement and the frequency are expanded into power series with respect to a control parameter. The nonlinear governing equation is transformed into a sequence of linear problems having the same stiffness matrix. Needing one matrix inversion, a large number of terms can be computed with a small computation time. Taking the starting point in the zone of validity, the method is reapplied in order to determine a further part of the nonlinear solution. In order to increase the zone of validity, the Pade approximants are incorporated. Iterations of this method lead to a powerful incremental method. Numerical tests for large amplitudes free vibrations of plates with various shapes and boundary conditions are reported. Recent improvements in the basic ANM algorithm as well as applications to various structural problems are added in order to exhibit the effectiveness and the applicability of this method.

Are small fishes more sensitive to habitat loss? A generic size-based model

2016 ◽  
Vol 73 (4) ◽  
pp. 716-726 ◽  
Author(s):  
Adam S. van der Lee ◽  
Marten A. Koops
Keyword(s):  
Life History ◽  
Habitat Loss ◽  
Small Species ◽  
Freshwater Biodiversity ◽  
Starting Point ◽  
Distinct Stage ◽  
Increased Sensitivity ◽  
Good Starting Point ◽  
Maximum Body ◽  
Maximum Body Length

Habitat loss represents the greatest threat to freshwater biodiversity. The potential for life history attributes to correlate with the risks associated with habitat loss represents a possible mechanism for more effective and rapid assessments, especially in data-limited situations. Body size correlates with many other life history attributes and is a good starting point for investigating correlates with habitat loss. Here, we use a generic stage-based matrix population model, parameterized using length-based allometries, to investigate if such a mechanism exists. Our analysis revealed that small species (shorter maximum body length) were initially more sensitive to the loss of habitat. Moreover, distinct stage-based patterns exist showing an increased sensitivity of population growth rate for small species to both habitat loss and vital rate perturbations of pre-adult stages. This indicates that the pre-adult period represents a critical stage for the continued production of small species and increased importance of the conservation of habitat used by young-of-the-year and juvenile fishes.

scholarly journals Modeling of the mechanical behavior of fiber-reinforced ceramic composites using finite element method (FEM)

2014 ◽  
Vol 46 (3) ◽  
pp. 385-390 ◽  
Author(s):  
M.M. Dimitrijevic ◽  
N. Tomic ◽  
B. Medjo ◽  
R. Jancic-Heinemann ◽  
M. Rakin ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mechanical Behavior ◽  
Ceramic Matrix Composites ◽  
Ceramic Composites ◽  
Elementary Cell ◽  
Fiber Reinforced ◽  
Starting Point ◽  
Fiber Matrix ◽  
Element Method

Modeling of the mechanical behavior of fiber-reinforced ceramic matrix composites (CMC) is presented by the example of Al2O3 fibers in an alumina based matrix. The starting point of the modeling is a substructure (elementary cell) which includes on a micromechanical scale the statistical properties of the fiber, matrix and fiber-matrix interface and their interactions. The numerical evaluation of the model is accomplished by means of the finite element method. The numerical results of calculating the elastic modulus of the composite dependance on the quantity of the fibers added and porosity was compared to experimental values of specimens having the same composition.

scholarly journals Investigation of the mechanical performance of fiber-modified ceramic composites using finite element method

2019 ◽  
Vol 13 (3) ◽  
pp. 173-179
Author(s):  
Majid Ahmadi ◽  
Seyed Hadi Seyedin ◽  
Seyed Vahid Seyedin
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Finite Element ◽  
Mechanical Performance ◽  
Porous Ceramic ◽  
Ceramic Composites ◽  
Material Structure ◽  
Composition Material ◽  
Starting Point ◽  
Element Method

Ceramic materials are widely used in impact safekeeping systems. Ceramic is a heterogeneous material; its characteristics depend considerably both on specifications of its ingredients and the material structure completely. The finite element method (FEM) can be a useful tool for strength computation of these materials. In this paper, the mechanical properties of the ceramic composites are investigated, and the mechanical performance modeling of fiber-fortified ceramic matrix composites (CMC) is expressed by the instance of aluminum oxide fibers in a matrix composite based on alumina. The starting point of the modeling is an infrastructure (primary cell) that contains a micromechanical size, the statistical analysis characteristics of the matrix, fiber-matrix interface, fiber, and their reciprocal influences. The numeral assessment of the model is done using the FEM. The numerical results of composite elastic modulus were computed based on the amount of the added fibers and the porosity was evaluated for empirical data of samples with a similar composition. Various scanning electron microscope (SEM) images were used for each sample to specify the porosity. Also, the unit cell method presumed that the porous ceramic substance is manufactured from an array of fundamental units, each with the same composition, material characteristic, and cell geometry. The results showed that when the material consists of different pores and fibers, the amount of Young’s modulus reduces with the increment of porosity. The linear correlation model of elasticity versus porosity value from experimental data was derived by MATLAB curve fitting. The experimental data from the mechanical test and numerical values were in good agreement.

Simulation of Thermo Mechanical Behavior of Structures by the Numerical Resolution of Direct Problem

2011 ◽  
Vol 61 ◽  
pp. 85-93
Author(s):  
B. Aouragh ◽  
J. Chaoufi ◽  
H. Fatmaoui ◽  
Jean Christophe Dupré ◽  
Claude Vallée ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Infrared Thermography ◽  
Direct Problem ◽  
The Finite Element Method ◽  
Numerical Techniques ◽  
Numerical Resolution ◽  
Starting Point ◽  
Experimental And Numerical Modeling ◽  
Element Method

The aim of our study is to develop an approach to both experimental and numerical modeling to the thermal behavior of a material by identifying these thermal parameters. The theoretical part is based on the finite element method which is a starting point to solve a two-dimensional inverse heat. The experimental measurements are performed by infrared thermography. All these experimental and numerical techniques give this method properties valued in the industrial world as the non-intrusive measurements and real-time calculations. For this, we have supported a system of equations and the temperature field, so before starting the inverse problem, we addressed the direct problem by finite element method that has been compared to measures experimental infrared thermography well to check the validity of equations, so it’s the purpose of this work.

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