Long-term static testing machine for plain and reinforced plastics

The influence of void content on the fracture performance of discontinuous long glass fibre reinforced injection molded polypropylene was studied. Compact tension specimens were machined from simple plate-tools and were loaded in a static testing machine in a laboratory environment. From the resulting load-displacement curves the fracture toughness was determined on the basis of the linear elastic fracture mechanics. It was found that higher void content causes a decrease in the fracture toughness.

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Programmed static testing machine for polymer materials

Polymer Mechanics ◽

10.1007/bf00855564 ◽

1972 ◽

Vol 5 (5) ◽

pp. 827-829

Author(s):

E. G. Isakovich

Keyword(s):

Testing Machine ◽

Polymer Materials ◽

Static Testing ◽

Static Testing Machine

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New possibilities for in situ CT analysis of additive manufactured samples

Czasopismo Techniczne ◽

10.37705/techtrans/e2020028 ◽

2020 ◽

pp. 1-9

Author(s):

Grzegorz Ziółkowski ◽

Grzegorz Treter ◽

Emilia Tokarczyk ◽

Patrycja Szymczyk-Ziółkowska

Keyword(s):

3D Imaging ◽

Testing Machine ◽

Tensile Tests ◽

Static Testing ◽

Industrial Computed Tomography ◽

Ct Analysis ◽

Manufacturing Methods ◽

Static Testing Machine ◽

In Situ Examination

Industrial Computed Tomography (CT) is a broadly used measurement method allowing for quality control of objects produced using additive manufacturing methods. The combination of tensile tests and simultaneous 3D imaging of the behavior of an object under a particular force (i.e. in situ examination – during the process) significantly broadens the possibilities of analyzing objects with a complex internal geometry. The purpose of this paper is to present the author’s project of a mini testing machine, to verify its functioning with regards to a static testing machine, and to present the initial in situ examination results for polymer samples.

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Effect of long climatic ageing on the microstructure of the surface of сarbon-fiber-reinforced plastics on base epoxy matrix

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2018-95-3-157-169 ◽

2019 ◽

pp. 157-169 ◽

Cited By ~ 1

Author(s):

I. S. Deev ◽

E. V. Kurshev ◽

S. L. Lonsky

Keyword(s):

Climatic Factors ◽

Temperate Climate ◽

Fiber Reinforced ◽

Humid Climate ◽

Climatic Zones ◽

Reinforced Plastics ◽

Carbon Plastics ◽

Fiber Reinforced Plastics ◽

Determining Factor

Studies and experimental data on the microstructure of the surface of samples of epoxy сarbon-fiber-reinforced plastics that have undergone long-term (up to 5 years) climatic aging in different climatic zones of Russia have been conducted: under conditions of the industrial zone of temperate climate (Moscow, MTsKI); temperate warm climate (Gelendzhik, GTsKI); a warm humid climate (Sochi, GNIP RAS). It is established that the determining factor for aging of carbon plastics is the duration of the complex effect of climatic factors: the longer the period of climatic aging, the more significant changes occur in the microstructure of the surface of the materials. The intensity of the aging process and the degree of microstructural changes in the surface of carbon plastics are affected by the features of the climatic zone. general regularities and features of the destruction of the surface of carbon plastics after a long-term exposure to climatic factors have been established on the basis of the analysis and systematization of the results of microstructural studies.

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Material Characterization of a Magnetorheological Fluid Subjected to Long-Term Operation in Damper

Materials ◽

10.3390/ma11112195 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2195 ◽

Cited By ~ 14

Author(s):

Dewi Utami ◽

Ubaidillah ◽

Saiful Mazlan ◽

Fitrian Imaduddin ◽

Nur Nordin ◽

...

Keyword(s):

Dynamic Testing ◽

Testing Machine ◽

Morphological Observation ◽

Magnetic Flux Density ◽

Damping Force ◽

Stroke Length ◽

Mr Fluid ◽

Term Operation ◽

Operating Cycles

This paper investigates the field-dependent rheological properties of magnetorheological (MR) fluid used to fill in MR dampers after long-term cyclic operation. For testing purposes, a meandering MR valve was customized to create a double-ended MR damper in which MR fluid flowed inside the valve due to the magnetic flux density. The test was conducted for 170,000 cycles using a fatigue dynamic testing machine which has 20 mm of stroke length and 0.4 Hz of frequency. Firstly, the damping force was investigated as the number of operating cycles increased. Secondly, the change in viscosity of the MR fluid was identified as in-use thickening (IUT). Finally, the morphological observation of MR particles was undertaken before and after the long-term operation. From these tests, it was demonstrated that the damping force increased as the number of operating cycles increases, both when the damper is turn on (on-state) and off (off-state). It is also observed that the particle size and shape changed due to the long operation, showing irregular particles.

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The Effect of Strain-Rate Upon the Tensile Deformation of Materials

Journal of Engineering Materials and Technology ◽

10.1115/1.3443275 ◽

1975 ◽

Vol 97 (2) ◽

pp. 151-155 ◽

Cited By ~ 49

Author(s):

R. G. Davies ◽

C. L. Magee

Keyword(s):

Flow Stress ◽

Strain Rate ◽

High Speed ◽

Tensile Deformation ◽

Rate Sensitivity ◽

Al Alloys ◽

Reinforced Plastics ◽

Strain Behavior ◽

Static Testing ◽

Dynamic Factors

The tensile strength of seventeen engineering materials including steels, Al alloys, and fiber-reinforced plastics, has been determined at strain-rates from 10−3 to 103 sec−1. Variable effects on the stress-strain behavior were found in the different materials with the Al alloys showing minimal strain-rate sensitivity and the plastics highest. All results exhibit a logarithmic dependence of flow stress on strain-rate and thus the dynamic factors (ratio of dynamic to low rate or quasi-static strengths) are as dependent upon changes in quasi-static testing speed (∼1 in./min (0.42 mm/s) as they are to changes at high speed (50,000 in./min or 50 mph (22.35 m/s). No significant influence of strain-rate on elongation or reduction in area has been found for any of the materials. Steels, which comprise the majority of the presently investigated materials, exhibit a higher rate sensitivity for yielding than for higher strain deformation. It is shown that the flow stress results for these steels leads to an internally consistent scheme when (1) strength level and (2) strengthening mechanisms are properly accounted for.

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Dynamic viscoelastic behavior of lower extremity tendons during simulated running

Journal of Applied Physiology ◽

10.1152/jappl.2000.89.4.1352 ◽

2000 ◽

Vol 89 (4) ◽

pp. 1352-1359 ◽

Cited By ~ 28

Author(s):

M. De Zee ◽

F. Bojsen-Møller ◽

M. Voigt

Keyword(s):

Cyclic Loading ◽

Achilles Tendon ◽

Testing Machine ◽

Viscoelastic Behavior ◽

Muscle Spindles ◽

Minor Effect ◽

Velocity Feedback ◽

Dynamic Creep

The aim of this project was to see whether the tendon would show creep during long-term dynamic loading (here referred to as dynamic creep). Pig tendons were loaded by a material-testing machine with a human Achilles tendon force profile (1.37 Hz, 3% strain, 1,600 cycles), which was obtained in an earlier in vivo experiment during running. All the pig tendons showed some dynamic creep during cyclic loading (between 0.23 ± 0.15 and 0.42 ± 0.21%, means ± SD). The pig tendon data were used as an input of a model to predict dynamic creep in the human Achilles tendon during running of a marathon and to evaluate whether there might consequently be an influence on group Ia afferent-mediated length and velocity feedback from muscle spindles. The predicted dynamic creep in the Achilles tendon was considered to be too small to have a significant influence on the length and velocity feedback from soleus during running. In spite of the characteristic nonlinear viscoelastic behavior of tendons, our results demonstrate that these properties have a minor effect on the ability of tendons to act as predictable, stable, and elastic force transmitters during long-term cyclic loading.

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Effect of Incisal Porcelain Veneering Thickness on the Fracture Resistance of CAD/CAM Zirconia All-Ceramic Anterior Crowns

International Journal of Dentistry ◽

10.1155/2019/6548519 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Noha Badran ◽

Sanaa Abdel Kader ◽

Fayza Alabbassy

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

Mode Iii ◽

Nickel Chromium ◽

Significant Difference ◽

All Ceramic ◽

Metal Ceramic ◽

Cad Cam ◽

Ceramic Crown

Statement of Problem. In some clinical situations, the vertical length of either a prepared tooth or an implant abutment is short, while the occlusal clearance to be restored by a porcelain crown is large. Incisal thickness of the veneering porcelain should be considered to prevent mechanical failure of the crown. Purpose. The aim of this study is to evaluate the effect of two different incisal veneering porcelain thickness on the fracture resistance of the anterior all-ceramic CAD/CAM zirconia crown system as compared with the conventionally used metal ceramic crown system. Method. CAD/CAM zirconia all-ceramic and metal ceramic crowns were fabricated on the prepared dies with standardized dimensions and designs using standardized methods according to the manufacturer’s instructions. All crowns were then adhesively luted with resin-based cement (Multilink cement system), subjected to thermal cycling and cyclic loading, and were loaded until fracture using the universal testing machine to indicate the fracture resistance for each crown material in each veneering thickness. Results. Statistical analysis was carried out, and the results showed that the fracture resistance of the nickel-chromium metal ceramic group was significantly higher than that of the CAD/CAM zirconia all-ceramic group. Also, the fracture resistance of crowns with 1.5 mm incisal veneering thickness was significantly higher than those with 3 mm incisal veneering thickness in both groups. Furthermore, there was no significant difference in the fracture mode of the two groups where 50% of the total specimens demonstrated Mode II (veneer chipping), while 35% demonstrated Mode I (visible crack) and only 15% demonstrated Mode III (bulk fracture). Conclusion. High failure load values were demonstrated by the specimens in this study, which suggest sufficient strength of both incisal veneering thickness in both crown systems to withstand clinical applications; however, the fracture patterns still underline the requirement of a core design that support a consistent thickness of the veneering ceramic, and it is recommended to conduct long-term prospective clinical studies to confirm findings reported in the present study.

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