Apparatus for strain and load cycling at elevated temperature with high-accuracy control during hold periods

1970 ◽  
Vol 5 (4) ◽  
pp. 284-291 ◽  
Author(s):  
D J White ◽  
G P Horwood ◽  
Z Czajkowski
Keyword(s):  
Load Capacity ◽  
Axial Strain ◽  
Testing Machine ◽  
Cyclic Stress ◽  
Hydraulic Testing ◽  
Gauge Length ◽  
Conic Section ◽  
Accuracy Control ◽  
Load Cycling ◽  
Better Than

A description is given of apparatus which has been developed to determine accurately the cyclic stress-strain behaviour of materials subjected to combined high-strain fatigue and creep at temperatures up to 700°C. The servo-hydraulic testing machine has a load capacity of ±20 000 lbf in push-pull and can operate in either a strain-cycling or a load-cycling mode. The specimen has a diameter of 0.5 in and a parallel gauge length of 1.5 in terminating in conic-section ridges on which extensometers are mounted for the measurement and control of axial strain. Strain is held constant to better than ±1 × 10−5 during hold times of up to 12 h and temperature control is better than ±0.5 degC.

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.

Experimental Study on the Combined Effect of Cyclic and Static Loads on the Mechanical Properties of the Saturated Soft Clay Material

2016 ◽  
Vol 723 ◽  
pp. 843-848
Author(s):  
Yi Wei ◽  
Ying Zhu ◽  
Jing Ni
Keyword(s):  
Mechanical Properties ◽  
Cyclic Load ◽  
Stress Ratio ◽  
Axial Strain ◽  
Soft Clay ◽  
Cyclic Stress ◽  
Excess Pore Pressure ◽  
Static Loads ◽  
Cyclic Stress Ratio ◽  
Excess Pore

The combined effect of cyclic and static loads on the mechanical properties of the soft clay was experimentally investigated by conducting undrained cyclic triaxial tests on Shanghai clay. The results show that an increment in either static or cyclic load increases excess pore pressures and axial strains. For a given value of combined cyclic and static loads, the mechanical properties of the soft clay are more sensitive to the cyclic load. Furthermore, the accumulated excess pore pressure and axial strain for a larger cyclic stress ratio and a lower combined stress ratio might overcome that for a lower cyclic stress ratio and a higher combined stress ratio. The mechanical properties of the soft clay after the cyclic load was unloaded were also discussed. It was observed that the excess pore pressure and axial strain under the static load alone decrease gradually with time. The trend of them largely depends on the ratio of cyclic load to static load.

scholarly journals Effects of temperature and impactor nose diameter on the impact behavior of PA6 and PP thermoplastic composites

2018 ◽  
Vol 51 (1) ◽  
pp. 64-74 ◽  
Author(s):  
Akar Dogan ◽  
Yusuf Arman
Keyword(s):  
Load Capacity ◽  
Testing Machine ◽  
Polyamide 6 ◽  
Impact Testing ◽  
Impact Behavior ◽  
Thermoplastic Composites ◽  
Test Machine ◽  
Effects Of Temperature ◽  
Impact Energies ◽  
The Impact

In this study, the effects of temperature and impactor nose diameter on the impact behavior of woven glass-reinforced polyamide 6 (PA6) and polypropylene (PP) thermoplastic composites were investigated experimentally. Impact energies are chosen as 10, 30, 50, 70, 90, 110, 130, and 170 J. The thickness of composite materials is 4 mm. Impact tests were performed using a drop weight impact testing machine, CEAST-Fractovis Plus, and the load capacity of test machine is 22 kN. Hemispherical impactor nose diameter of 12, 7, and 20 mm were used as an impactor. The tests are conducted at room temperature (20°C and 75°C). As a result, the PP composites of the same thickness absorbed more energy than PA6 composites. The amount of absorbed energy of PP and PA6 composites decreased with temperature.

Dynamic Behaviour of Reinforcing Steel Bars in Tension

2011 ◽  
Vol 82 ◽  
pp. 86-91 ◽  
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni ◽  
Nicoletta Tesio
Keyword(s):  
Testing Machine ◽  
Maximum Load ◽  
Gauge Length ◽  
Strain Rates ◽  
Reinforcing Bars ◽  
Static Tests ◽  
Split Hopkinson Tensile Bar ◽  
Steel Bars ◽  
Split Hopkinson ◽  
Reinforced Steel

In this paper the preliminary results of the tensile behavior of reinforced steel in a large range of strain rates are presented. Tensile testing at several strain rates, using different experimental set-ups, was carried out. For the quasi-static tests a universal electromechanical testing machine with the maximum load-bearing capacity of 50 kN was used, while for the intermediate and high-strain rate regimes a hydro-pneumatic apparatus and a JRC-Split Hopkinson Tensile Bar respectively were used. The target strain rates were set at the following five levels: 10-3, 30, 250, 500, and 1000 1/s. The specimens used in this research were round samples having 3mm in diameter and 5mm of gauge length obtained from reinforcing bars. Finally, the material parameters for Cowper-Symonds and Johnson-Cook models were determined.

scholarly journals Effect of Variable Confining Pressure on Cyclic Triaxial Behavior of K0-consolidated Soft Marine Clay

2018 ◽  
Vol 4 (4) ◽  
pp. 755
Author(s):  
Lei Sun
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Confining Pressure ◽  
Stress Path ◽  
Cyclic Stress ◽  
Marine Clay ◽  
Stress Ratios ◽  
Variable Confining Pressure

The effect of variable confining pressure (VCP) on the cyclic deformation and cyclic pore water pressure in K0-consolidated saturated soft marine clay were investigated with the help of the cyclic stress-controlled advanced dynamic triaxial test in undrained condition. The testing program encompassed three cyclic deviator stress ratios, CSR=0.189, 0.284 and 0.379 and three stress path inclinations ηampl=3,1 and 0.64. All tests with constant confining pressure (CCP) and variable confining pressure (VCP) have identical initial stress and average stress. The results were analyzed in terms of the accumulative normalized excess pore water pressure rqu recorded at the end of each stress cycle and permanent axial strain, as well as resilient modulus. Limited data suggest that these behavior are significantly affected by both of the VCP and CSR. For a given value of VCP, both of the pore water pressure rqu and permanent axial strains are consistently increase with the increasing values of CSR. However, for a given value of CSR, the extent of the influence of VCP and the trend is substantially depend on the CSR.

scholarly journals Experimental and Simulation Investigation of Bending Moment Effect on Hollow Columns of Multi-layers of Hybrid Materials

2019 ◽  
Vol 12 (1) ◽  
pp. 44-55
Author(s):  
Ayad A. Ramadhan
Keyword(s):  
Hybrid Materials ◽  
Volume Fraction ◽  
Load Capacity ◽  
Testing Machine ◽  
Bending Moment ◽  
Maximum Load ◽  
Experimental Procedure ◽  
Bending Load ◽  
Alumina Composite ◽  
Moment Effect

This paper presented the effect of bending on multi-layer of hollow columns of Hybrid materials (Carbon-Glass /epoxy-Alumina) composite this effect occurred and volume fraction of fibers. An experimental procedure was developed to study the performance of these effects under bending load using a hydraulic bending device type (MATEST. SRL) testing machine. This study has three forms through the selection of columns hollows width to thickness (a/b) (0.5, 1 and 2) with three types of layers of samples (2,4 and8) layers. The ultimate load of failure for each Hybrid/epoxy-Al2O3 had been determined and specified the optimum volume fraction (Vf) due to the effect of mixing 50% and 60% were low in the case for compared 55% volume fraction. To simulate this problem the researcher used Explicit Mesh for AUTODYN under ANSYS-15 software, it was found that maximum bending load for Hybrid/ Epoxy-Al2O3 Specimens, the maximum load of specimens increased with increasing number of layers from 2L to 8L. The results also identified that the maximum load capacity by 55% volume fraction and a/b=0.5 of all composite specimens was highest from the others types of (50% and 60%) volume fractions and (a/b=1 and a/b=2) .Also, the Increasing ratio of stress capacity for specimens have 4 to 2 layers (4/2)  and 8 to 4  (8/4) for experimental results have maximum value with increasing by 48.19%  and 46.84% at (Sp.4#8/Sp.2#4) and (Sp.8#6/Sp.4#6) respectively.

Influence of Liquid Paraffins in Crude Oil on the Friction and Wear Behaviors of the Progressing Cavity Pump`s Stator Rubber

2013 ◽  
Vol 300-301 ◽  
pp. 833-836
Author(s):  
Shi Jie Wang ◽  
Hao Lin ◽  
Xiao Ren Lv
Keyword(s):  
Crude Oil ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Liquid Paraffin ◽  
Testing Machine ◽  
Wear Testing ◽  
Wear Loss ◽  
Oil Well ◽  
Butadiene Rubber ◽  
Better Than

The progressing cavity pump (PCP) always works in the waxy oil well. Therefore the research on the influence of various liquid paraffin contents in crude oil on the friction and wear behaviors of the progressing cavity pump`s stator is very important for choosing the best stator rubber and developing the service life of PCP. Wear behavior of nitrile butadiene rubber (NBR) and fluororubber (FKM) was investigated at room temperature using a reciprocating friction and wear testing machine under the various paraffin contents in crude oil (0%、10%、30%、50%、100%). The wear morphology of blend was analyzed through the stereomicroscope and the wear behavior of two blends was also discussed and compared. The results show that the wear resistance of FKM is better than that of NBR under the same paraffin content in crude oil; With the increase of the paraffin content, the wear and coefficient of friction also increase. When the paraffin content in crude oil is less than 30%, the wear loss of NBR and FKM are basically the same; When the paraffin content in crude oil is more than 30%, the wear loss of NBR is far more than that of FKM.

Liquefaction Susceptibility of Silty Sands and Low Plastic Clay Soils

2019 ◽  
Vol 10 (2) ◽  
pp. 1-17
Author(s):  
Akhila M. ◽  
Rangaswamy K. ◽  
Sankar N.
Keyword(s):  
Axial Strain ◽  
Clay Fraction ◽  
Fine Sand ◽  
Cyclic Stress ◽  
Clay Soils ◽  
Liquefaction Resistance ◽  
Plastic Clay ◽  
Liquefaction Susceptibility ◽  
Soil Mixtures ◽  
Plastic Clays

The present study evaluates the liquefaction susceptibility of non-plastic silty sands and low plastic clay soils at different cyclic stress levels under undrained triaxial loading conditions. Six different types of soil combinations were prepared after blending the silt and clay fractions into the fine sand. Silty sands contain up to 40% non-plastic fines and low plastic clays comprise 10-20% clay fraction. The cylindrical soil specimens were constituted at the medium relative density and isotropically consolidated at 100 kPa pressure. The consolidated specimens were subjected to cyclic stress amplitudes of 0.127, 0.152 and 0.178 using sinusoidal wave loading at a frequency of 1 Hz. Results were presented in terms of pore pressure build-up and axial strain propagation with load cycles, and liquefaction resistance curves. It was found that the non-plastic silty sands and soil mixtures with plasticity indices up to 15 are more susceptible to liquefaction than the fine sands. The criterion on liquefaction susceptibility of low plastic soil mixtures shows that the soil mixtures with plasticity indices up to 15 containing 20% plastic fines exhibit a sand-like behavior and show higher liquefaction susceptibility than fine sands. It is worthy to note that the low plastic soil mixtures with PI ≥ 10 are more resistant to liquefaction than the silty sands (those contain up to 40% non-plastic fines).

Sign in / Sign up

Export Citation Format

Share Document