Experimental System and Validation for Energy-Based Characterization

2011 ◽  
Author(s):  
Jan Wei Pan ◽  
Jinquan Cheng ◽  
Tomonari Furukawa ◽  
Athanasios P. Iliopoulos ◽  
John G. Michopoulos
Keyword(s):  
Elastic Constants ◽  
Testing Machine ◽  
Experimental System ◽  
Tensile Tests ◽  
Recursive Estimation ◽  
Sensor Data ◽  
External Work ◽  
Measurement Results ◽  
Uniaxial Testing ◽  
Open Hole

This paper presents the experimental system and experimental validation of an energy-based characterization for the identification of elastic constants. Unlike the standard uniaxial testing machine, which uses a contact strain sensor such as extensometer, the developed system uses a non-contact optic sensor as an advantage to measure and derive external work and strain measurements for characterizing the elastic constants. To investigate the validity of the energy-based characterization, a graphical user interface and the experimental system were developed for the tensile tests of aluminum open-hole specimens. During the validation, the means and variances of the characterization results were analyzed. The reliability of its recursive estimation was further investigated by the convergence of covariance at every new measurement. Results showed that the recursive estimation allows identification of elastic constants of a test coupon at every acquisition of sensor data in an online manner. The identification of all the constants during deformation thus demonstrated the overall validity and efficiency of the energy-based characterization.

Study of Bismuth Telluride Crystal Strength

2019 ◽  
pp. 1-8
Author(s):  
A. A. Gorbatovskiy
Keyword(s):  
Tensile Strength ◽  
Bismuth Telluride ◽  
Elasticity Modulus ◽  
Testing Machine ◽  
Bend Testing ◽  
Instron Testing Machine ◽  
Measurement Results ◽  
Strength Tests ◽  
Semiconductor Properties

The article presents results of strength tests of bismuth telluride prismatic samples obtained by growing crystals. These crystals have semiconductor properties and are used in the heat machines, the run-ability of which largely depends on the strength of crystals. Data available in the literature are significantly different from each other. It has been shown that, the most consistent strength tests results are obtained in case of bend testing. The measurement results of the elasticity modulus and tensile strength are given. For tests, an INSTRON testing machine with maximum direct stress of the 1000 H was used.

scholarly journals The Performance of CR180IF and DP600 Laser Welded Steel Sheets under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1553
Author(s):  
Mária Mihaliková ◽  
Kristína Zgodavová ◽  
Peter Bober ◽  
Anna Špegárová
Keyword(s):  
Sheet Steel ◽  
Testing Machine ◽  
Dynamic Test ◽  
Tensile Tests ◽  
Joint Surface ◽  
Strain Rates ◽  
Interstitial Free ◽  
Welded Steel ◽  
Steel Sheets ◽  
Static Tensile

The presented research background is a car body manufacturer’s request to test the car body’s components welded from dissimilar steel sheets. In view of the vehicle crew’s protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Static tensile tests were carried out by using testing machine Zwick 1387, and dynamic test used rotary hammer machine RSO. Sheet steel was tested at different strain rates ranging from 10−3 to 103 s−1. The laser welds’ microstructure and microhardness were evaluated in the base metal, heat-affected zone, and fusion zone. The comprehensive analysis also included chemical analysis, fracture surface analysis, and roughness measurement. The research results showed that the strain rate had an influence on the mechanical properties of base materials and welded joints. The dynamic loading increases the yield stress more than the ultimate tensile strength for the monitored steels, while the most significant increase was recorded for the welded material.

Using Embossing to Create a Fiber Reinforced Honeycomb Composite

2005 ◽  
Vol 127 (2) ◽  
pp. 257-262 ◽  
Author(s):  
William Jordan
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Carbon Fibers ◽  
Flexural Modulus ◽  
Testing Machine ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Hydraulic Testing ◽  
Charpy Impact Toughness ◽  
Bend Tests

This research project used hot embossing to create a strong and tough polymeric based composite structure. A honeycomb type structure was created by pressing small grooves into thin polycarbonate sheets. A trapezoidal die was used to create hexagonal shaped channels in the polymeric sheet. A number of these sheets were then bonded together to form a composite material. Carbon fibers were embedded into the channels in some of the laminates. The embossing process was carried out at an elevated temperature in an environmental chamber attached to an MTS servo hydraulic testing machine. The grooved structure had a 31% to 45% decrease in the apparent density compared to the ungrooved specimens. Bend tests, tensile tests, and Charpy impact tests were performed on laminates made from this material. The specific values of tensile strength, flexural modulus, and Charpy impact toughness were increased. A small percentage of fibers significantly increased both the stiffness and strength of the laminate.

On the implementation of FEA for the design and development of a new biaxial tensile test fixture for uniaxial testing machine: a validation for cruciform test specimens

2019 ◽  
Vol 41 (9) ◽  
Author(s):  
Luis Fernando Puente Medellín ◽  
Víctor Alfonso Ramírez Elías ◽  
Antonio de Jesús Balvantín García ◽  
Perla Iris Vázquez Gómez ◽  
José Angel Diosdado De la Peña
Keyword(s):  
Tensile Test ◽  
Testing Machine ◽  
Design And Development ◽  
Test Fixture ◽  
Biaxial Tensile Test ◽  
Biaxial Tensile ◽  
Uniaxial Testing

scholarly journals Mathematical Model of Communication Delays in Wireless Networks

2016 ◽  
Vol 62 (1) ◽  
pp. 61-64
Author(s):  
Beata Krupanek ◽  
Ryszard Bogacz
Keyword(s):  
Wireless Networks ◽  
Probabilistic Models ◽  
Experimental System ◽  
Delta Function ◽  
Access Time ◽  
Model Parameters ◽  
Communication Delays ◽  
Proposed Model ◽  
Measurement Results ◽  
Wireless Medium

Abstract The paper presents a new conception of building probabilistic models of communication delays in wireless networks that basis on using a delta function sequence to describe retransmissions between a transmitter and a receiver. It is assumed that the access time of the transmitter is described by a probability density function and the communication channel established in the wireless medium is disturbed by passive or active factors which cause that the transmission can be not correct and the sent data have to be retransmitted. Theoretical considerations have been verified by measurement results obtained by using the experimental system developed for investigating delays caused by external disturbances influencing the wireless transmission. A method of identification of the proposed model parameters and verification of the identified values has been presented.

Effect of Loading Rate on Tensile Properties of Automotive Steel Sheet

2013 ◽  
Vol 690-693 ◽  
pp. 211-217
Author(s):  
Jin Gui Qin ◽  
Fang Yun Lu ◽  
Yu Liang Lin ◽  
Xue Jun Wen
Keyword(s):  
Strain Rate ◽  
Testing Machine ◽  
Structural Response ◽  
Tensile Tests ◽  
Dynamic Tests ◽  
Static Tests ◽  
Split Hopkinson Tensile Bar ◽  
Axial Tensile ◽  
Static Tensile ◽  
Cook Model

Results of uni-axial tensile loading of three automotive steels at different strain rates (0.0011–3200s-1) are reported here. Quasi-static tensile tests were performed under the strain rate of 1.1×10-3 s-1 using an electromechanical universal testing machine, whereas dynamic tests were carried out under the strain rate in the range of 1100 to 3200 s-1 using a Split Hopkinson Tensile Bar apparatus. Based on the experimental results, the material parameters of widely used Johnson–Cook model which described the strain rate and temperature-dependent of mechanical behaviour were determined. The experiments show that strain-rate hardening is superior to thermal softening: yield stresses, tensile strength, deformation, and energy dissipation increase with the strain rate from quasi-static tests to dynamic tests. The Johnson–Cook model can describe the behaviour of these steels and provides the opportunity to study the material and structural response.

Evaluation of Slip Resistance of Safety Footwear Using Novel Equipment

2014 ◽  
Vol 627 ◽  
pp. 461-464
Author(s):  
C.H. Bang ◽  
Tae Gu Kim ◽  
J.S. Kim
Keyword(s):  
Occupational Safety ◽  
Testing Machine ◽  
Surface Characteristics ◽  
Major Effect ◽  
The Past ◽  
Safety And Health ◽  
Slip Resistance ◽  
Measurement Results ◽  
Korean Market ◽  
Design Factors

There are several causes of slip and fall accidents, such as floor and outsole surface characteristics, contaminants, environmental and human factors, and cognition. In relation to controllable causes, floor and outsole surface characteristics have been frequently investigated over the past decades. The characteristics of safety footwear outsoles, such as roughness, hardness, and tread pattern, tend to differ from those of casual shoes on the Korean market. The aim of this study is to investigate the slip resistance of safety footwear on the Korean market and determine the major design factors to improve the slip resistance. All friction tests were performed using the Korean Occupational Safety and Health Agency’s newly developed testing machine. Twenty-eight safety shoes were used in this experiment, and all friction tests were conducted under three different contamination conditions, namely water, detergent, and glycerol. The friction measurement results show that the hardness, material, and patterns of outsoles had a major effect on the slip resistance, but the effects were not statistically significant for some safety footwear. In general, safety footwear that had a number of small extruded blocks shows good slip resistance. Safety footwear patterns that have many small raised blocks on the heel have a higher friction coefficient than the others. A lower outsole hardness also gives a higher coefficient of friction.

Fatigue Properties of Al-Li Plates Joined by Friction Stir Welding

2008 ◽  
Vol 385-387 ◽  
pp. 849-852 ◽  
Author(s):  
Pasquale Cavaliere ◽  
Francesco W. Panella ◽  
Antonio Squillace
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Testing Machine ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Control Mode ◽  
Fatigue Properties ◽  
Amplitude Control ◽  
Friction Stir

Al-Li alloys are characterized by a strong anisotropy in mechanical properties and microstructure with respect to the rolling direction. Plates of 2198 Al-Li alloy were friction stir welded by employing maximum rotation speed: 1000 rev/min and welding speed of 80 mm/min, both in parallel and orthogonal directions with respect to the rolling one. The joints mechanical properties were evaluated by means of tensile tests at room temperature. In addition, fatigue tests performed with a resonant electro-mechanical testing machine under constant amplitude control up to 250 Hz loading, were conducted in axial control mode with R(σmin/σmax)=0.33, for all the welding and rotating speed conditions. The fatigue crack propagation experiments were performed by employing single edge notched specimens.With the aim to characterize the weld performances, both the microstructure evolution at jointed cross sections, related to the welding variables, and the fractured surfaces were respectively analyzed by means of optical and scanning electron microscopy.

Design of a biaxial test module for uniaxial testing machine

2017 ◽  
Vol 4 (8) ◽  
pp. 7911-7920 ◽  
Author(s):  
Luis Fernando Puente Medellín ◽  
José Ángel Diosdado De la Peña
Keyword(s):  
Testing Machine ◽  
Biaxial Test ◽  
Uniaxial Testing ◽  
Test Module
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