A study of temperature rise in oil due to compression

1998 ◽  
Vol 212 (4) ◽  
pp. 291-299 ◽  
Author(s):  
K Imado ◽  
Y Kido ◽  
H Miyagawa ◽  
F Hirano
Keyword(s):  
Temperature Rise ◽  
Impact Test ◽  
Volumetric Strain ◽  
Viscosity Coefficient ◽  
Maximum Temperature ◽  
Compression Tests ◽  
Maximum Acceleration ◽  
Impact Tests ◽  
Higher Temperature ◽  
The Impact

Temperature rises of various oils were measured in both impact tests and quasi-adiabatic compression tests. A steel ball impacted against an oiled sapphire glass in the impact test. It was found that the maximum temperature rise was 45 °C in impact tests. A close relationship between temperature rise and α amax was found for oils of relatively low viscosity, where α was the pressure-viscosity coefficient and amax was the maximum acceleration of the hammer during impact; namely, the temperature increased with each increase in the product of the contact force and the pressure-viscosity coefficient. In the compression tests, the temperature increased almost linearly with increase in the volumetric strain regardless of the type of oil. The order of the temperature rise for the corresponding oil in each experiment was reversed; i.e. a higher temperature increase was observed for an oil of smaller pressure-viscosity coefficient in the compression test. On the contrary, a higher temperature rise was noted in the case of a larger pressure-viscosity coefficient in the impact test. As far as the temperature rise is concerned for entrapped oil in the impact tests, there exists an optimum combination of viscosity and pressure-viscosity coefficient.

Investigation of Impact Test of Power Battery under Different Environment Temperatures

2012 ◽  
Vol 229-231 ◽  
pp. 1064-1067
Author(s):  
Hong Wei Wang ◽  
Jun Liu ◽  
Hai Qing Xiao ◽  
Chao Wang
Keyword(s):  
Temperature Rise ◽  
Thermal Runaway ◽  
Maximum Temperature ◽  
Exothermic Effect ◽  
Impact Tests ◽  
Power Battery ◽  
Rise Rate ◽  
Environment Temperature ◽  
Relationship Of ◽  
The Impact

The impact tests are generally performed at room temperature in actual standards, but in fact, the power battery work in variety of different environment temperatures. Therefore, the impact tests of the power battery were researched at different environment temperatures (-30°C, 20°C, 40°C and 65°C). The results showed that the impact can induce the internal short circuit, at the same time, if battery system is kept running at high environment temperature, the exothermic effect will induce the heat accumulation inside the battery, leading to thermal runaway and even the battery burning and explosion. The other result is that the higher the environment temperature is, the worse the battery thermal stability is. Temperature rise rate and maximum temperature was a linear relationship of the samples that did not burn during impact tests. And the temperature rise rate and maximum temperature was the cubic polynomial relationship of the samples that burn during impact tests. That is to say, the battery is prone to induce thermal runaway when the temperature rise rate is high.

Experimental investigation of the quasi-static and impact tests on the energy absorption characteristics of coupler rubber buffers used in railway vehicles

2018 ◽  
Vol 233 (9) ◽  
pp. 937-950 ◽  
Author(s):  
Shuguang Yao ◽  
Zhixiang Li ◽  
Wen Ma ◽  
Ping Xu ◽  
Quanwei Che
Keyword(s):  
Energy Absorption ◽  
Impact Velocity ◽  
High Speed ◽  
Compression Tests ◽  
Static Compression ◽  
Static Tests ◽  
Impact Tests ◽  
High Speed Trains ◽  
The Impact ◽  
Absorption Characteristics

Coupler rubber buffers are widely used in high-speed trains, to dissipate the impact energy between vehicles. The rubber buffer consists of two groups of rubbers, which are pre-compressed and then installed into the frame body. This paper specifically focuses on the energy absorption characteristics of the rubber buffers. Firstly, quasi-static compression tests were carried out for one and three pairs of rubber sheets, and the relationship between the energy absorption responses, i.e. Eabn  =  n ×  Eab1, Edissn =  n ×  Ediss1, and Ean =  Ea1, was obtained. Next, a series of quasi-static tests were performed for one pair of rubber sheet to investigate the energy absorption performance with different compression ratios of the rubber buffers. Then, impact tests with five impact velocities were conducted, and the coupler knuckle was destroyed when the impact velocity was 10.807 km/h. The results of the impact tests showed that with the increase of the impact velocity, the Eab, Ediss, and Ea of the rear buffer increased significantly, but the three responses of the front buffer did not increase much. Finally, the results of the impact tests and quasi-static tests were contrastively analyzed, which showed that with the increase of the stroke, the values of Eab, Ediss, and Ea increased. However, the increasing rates of the impact tests were higher than that of the quasi-static tests. The maximum value of Ea was 68.76% in the impact tests, which was relatively a high value for the vehicle coupler buffer. The energy capacity of the rear buffer for dynamic loading was determined as 22.98 kJ.

scholarly journals Effect of Low and High Viscosity Composites on Temperature Rise of Premolars Restored through the Bulk-Fill and the Incremental Layering Techniques

2020 ◽  
Vol 10 (22) ◽  
pp. 8041
Author(s):  
Roberto De Santis ◽  
Vito Gallicchio ◽  
Vincenzo Lodato ◽  
Sandro Rengo ◽  
Alessandra Valletta ◽  
...  
Keyword(s):  
Temperature Rise ◽  
High Viscosity ◽  
Single Step ◽  
Maximum Temperature ◽  
Main Concern ◽  
Light Curing ◽  
Higher Temperature ◽  
Temperature Rate ◽  
Dental Cavities ◽  
Flowable Composites

Background: Deep dental cavities can be restored through a single step according to the bulk-fill technique. Due to the great amount of resin to be cured, a main concern is the temperature rise occurring in the pulp chamber, potentially higher than that developed through the incremental layering technique. Temperature rise of bulk-fill composites have been evaluated. Methods: Bulk-fill composites, differing in material composition and viscosity, were used. Maximum temperature and temperature rate occurring in the composites were measured. Mesio-occlusal-distal cavities of human premolars were restored through the bulk-fill or the incremental layering techniques, and peak temperature and temperature rate occurring in the dentin, 1 mm below the cavity floor, were evaluated. Results: Temperature peak and temperature rise of flowable composites were significantly higher (p < 0.05) than packable composites. For both the techniques, higher temperature peaks were recorded in the dentin for flowable composites. Peak temperatures higher than 42 °C were recorded for the incremental layering technique considering flowable composites. Conclusions: For all the composites, the light curing modality of 1000 mW/cm2 for 20 s can be considered safe if the bulk-fill technique is performed. Instead, for the incremental layering technique, potentially dangerous temperature peaks have been recorded for flowable composites.

Relationship Between Charpy V-Notch Impact Value and Fracture Mechanics Toughness: Added Value of Finite Element Analysis and Instrumented Impact Tests

2011 ◽  
Author(s):  
Philippe Thibaux ◽  
Filip Van den Abeele ◽  
Philippe Burlot
Keyword(s):  
Finite Element ◽  
Master Curve ◽  
Impact Test ◽  
Crack Arrest ◽  
Smooth Transition ◽  
Unstable Crack ◽  
Impact Tests ◽  
The Difference ◽  
Energy Dissipated ◽  
The Impact

Each structure is designed with resistance versus the fracture, which requires the knowledge of the fracture resistance of the material. If no fracture mechanics data of the material is available, a KJC can be inferred from the master curve approach. The master curve approach relates a fracture toughness of 100 MPAm1/2 to the impact transition temperature T27J with a shift of 18°C. Although this relationship was successfully applied to a large number of experiments, some steels deviate significantly from the previous relationship, which can even lead to non-conservative design. In the present paper, instrumented impact tests (Charpy V-Notch CVN) and compact tensile (CT) tests were performed on two materials, one thermomechanically (TM-) rolled and one normalized steel. The difference between T0 and T27J was found to be different for these materials. Furthermore, the normalized steel exhibits a smooth transition from brittle to ductile behaviour, while the TM-rolled material shows a very steep transition. Extra information is gained by combining the instrumentation of the impact test and the finite element simulations of both the CT and impact tests. From the instrumented tests, it is also possible to determine the load at unstable crack propagation, the amount of energy dissipated at that moment, the load at crack arrest and the energy dissipated after crack arrest. From the finite element simulation, one learns about the constraints ahead of the crack tip for both configurations. The investigation teaches us that the smooth transition of the normalized material is related to a high energy dissipated after crack arrest, while the TM-rolled material has a much lower crack arrest load. The difference between T0 and T27J is then discussed by decomposing the total energy in the impact test between crack initiation, propagation and arrest. It is compared with KJC, which determines the toughness at unstable crack propagation, by reviewing the literature and local stress states computed from finite element.

Impact Behaviour of Composite Materials by Using Low and High Speed Impact Tests

2012 ◽  
Vol 445 ◽  
pp. 189-194
Author(s):  
Enver Bulent Yalcin ◽  
Volkan Gunay ◽  
Muzeyyen Marsoglu
Keyword(s):  
Composite Materials ◽  
High Speed ◽  
Impact Test ◽  
Woven Fabrics ◽  
Impact Behaviour ◽  
High Speed Impact ◽  
Impact Tests ◽  
Data Acquisition Software ◽  
Damage Process ◽  
The Impact

The study presents the need for instrumented testing to optimizing materials against impact forces. The objective of the study is how the impact behaviour of composite materials is investigated by slow and high speed impact tests. Instron Dynatup 9250HV and Instron Dynatup 8150 Impact test machines (Fig.1.) are used which are located in TUBITAK-MRC, Materials Institute , Impact Test Laboratory". The damage process in composite materials under low and high velocity impact loading and the impact energy-displacement properties of the composite materials were investigated. Composite samples were produced by woven fabrics. The results are given as graphs and tables. The Impulse Data Acquisition software is used to send the data to computer.

scholarly journals Analysis of Impact Characteristics and Detection of Internal Defects for Unidirectional Carbon Composites with Respect to Fiber Orientation

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 203
Author(s):  
Sun-ho Go ◽  
Alexandre Tugirumubano ◽  
Hong-gun Kim
Keyword(s):  
Carbon Fiber ◽  
Impact Test ◽  
Carbon Fiber Composites ◽  
Internal Defects ◽  
Impact Tests ◽  
Drop Weight ◽  
Weight Impact ◽  
Fibers Orientation ◽  
Lock In ◽  
The Impact

With the increasing use of carbon fiber reinforced plastics in various fields, carbon fiber composites based on prepregs have attracted attention in industries and academia research. However, prepreg manufacturing processes are costly, and the strength of structures varies depending on the orientation and defects (pores and delamination). For the non-contact evaluation of internal defects, the lock-in infrared thermography was proposed to investigate the defects in the composites subjected to the compression after impact test (CAI). The drop-weight impact test was conducted to study the impact behavior of the composites according to fibers orientation for composite fabricated using unidirectional (UD) carbon fiber prepregs. Using CAI tests, the residual compressive strengths were determined, and the damage modes were detected using a thermal camera. The results of the drop weight impact tests showed that the specimen laminated at 0° suffered the largest damage because of susceptibility of the resin to impact. The specimens with 0°/90° and +45°/−45° fibers orientation exhibited more than 90% of the impact energy absorption and good impact resistance. Furthermore, the specimens that underwent the impact tests were subjected to compressive test simultaneously with the lock-in thermography defects detection. The results showed that internal delamination, fibers splitting, and broken fibers occurred. The temperature differences in the residual compression tests were not significant.

scholarly journals Impact Tests of UHSS Steel Welded Joints Using the Drop - Tower Impact Drop Method

2019 ◽  
Vol 19 (3) ◽  
pp. 19-31
Author(s):  
J. Dorożyński ◽  
J. Nowacki ◽  
A. Sajek
Keyword(s):  
Impact Strength ◽  
Welded Joints ◽  
Impact Test ◽  
Gma Welding ◽  
High Strength ◽  
Test Method ◽  
Drop Tower ◽  
Current Application ◽  
Impact Tests ◽  
The Impact

AbstractThe article characterizes the impact test method using Drop-Tower Impact Test with the registration of the value of force and energy of breaking. Based on sources, the possibilities and scope of the current application of this method were determined and the current state of knowledge on the results of these tests was reviewed. In order to determine the possibility of using the method in impact tests of high strength steel joints, investigations of hybrid PTA - GMA welding conditions on impact strength of joints of MART S1300QL steel were carried out. In particular, the influence of t8/5 cooling time on the impact strength of welded joints by the Drop - Tower Impact Test method was determined. It has been shown that the use of dropping machine with computer-based registration of breaking force and energy values was possible in the case of impact strength testing of UHSS welded joints and enabled precise analysis of the energy distribution dynamics absorbed by the tested.

Improvement of Biocomposite Performance under Low-Velocity Impact Test - A Review

2021 ◽  
Vol 893 ◽  
pp. 67-74
Author(s):  
Usha Kiran Sanivada ◽  
Gonzalo Mármol ◽  
Francisco P. Brito ◽  
Raul Fangueiro
Keyword(s):  
Composite Structures ◽  
Impact Test ◽  
Impact Resistance ◽  
Vital Role ◽  
Low Velocity Impact ◽  
Efficient Design ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Tests ◽  
The Impact

The study of the impact energy and the composite behaviour plays a vital role in the efficient design of composite structures. Among the various categories of impact tests, it is essential to study low-velocity impact tests as the damage generated due to these loads is often not visible to the naked eye. The internal damages can reduce the strength of the composites and hence the impact behaviour must be addressed specifically for improving their applications in the transport industry. The main aim of this paper is to provide a comprehensive review of the work focusing on the assessment of biocomposites performance under low impact velocity, the different deformations, and damage mechanisms, as well the methods to improve the impact resistance.

The effect of high-temperature steam ingestion on aerodynamic performance and stability of a transonic rotor

2018 ◽  
Vol 233 (9) ◽  
pp. 3351-3367 ◽  
Author(s):  
Baofeng Tu ◽  
Luyao Zhang ◽  
Jun Hu
Keyword(s):  
High Temperature ◽  
Temperature Rise ◽  
Mass Fraction ◽  
Stability Boundary ◽  
Maximum Temperature ◽  
Aerodynamic Stability ◽  
Rise Rate ◽  
High Temperature Steam ◽  
The Impact ◽  
Transonic Rotor

To investigate the effect of high-temperature steam ingestion on the aerodynamic stability of a transonic axial compressor, a NASA Rotor 37 was numerically simulated. The effects of the high-temperature steam mass fraction, the temperature rise rate, the maximum temperature, and the distribution of steam at the inlet boundary on the aerodynamic stability of a transonic axial rotor were investigated, using the steady-state and quasi-steady methods. From the simulation results, it was found that high-temperature steam ingestion has an adverse effect on the transonic rotor. The greater the steam mass fraction and the maximum temperature, the greater the impact of the steam ingestion on the stability boundary. The temperature rise rate has little effect on the performance and stability. The distribution of steam at the inlet boundary has a significant impact on the performance and stability. In addition, with the ingestion of high-temperature steam, the average density of the gas at the rotor inlet is affected, and the passage shock position moves forward at the same time, which leads to the occurrence of the stall in advance.

scholarly journals Analysis of Impact Characteristics and Detection of Internal Defects for Unidirectional Carbon Composites with Respect to Fiber Orientation

2020 ◽  
Author(s):  
Sun-ho Go ◽  
Alexandre Tugirumubano ◽  
and Hong-gun Kim
Keyword(s):  
Carbon Fiber ◽  
Carbon Fiber Composites ◽  
Compression Tests ◽  
Internal Defects ◽  
Finite Elements Analysis ◽  
Impact Tests ◽  
Drop Weight ◽  
Weight Impact ◽  
Lock In ◽  
The Impact

.With the increasing use of carbon fiber reinforced plastics in various area, carbon fiber composites based on prepregs have attracted attention in industries and academia research. However, prepreg manufacturing processes are costly, and the strength of structures varies depending on the orientation and defects (pores and delamination). For non-contact evaluation of internal defects, we proposed lock-in infrared thermography to investigate orientation angles after a compression test. We also conducted a drop-weight impact test to study the behaviour of the composites after impact according the fibers orientation for composite fabricated using unidirectional carbon fiber prepregs. Using CAI tests, we determined the residual compressive strength and confirmed the damage modes using a thermal camera. The results of the drop weight impact tests show that the specimen laminated at 0&deg; suffered the largest damage because of susceptibility of the resin to impact. In contrast, the specimens oriented in of 0&deg;/90&deg; and +45&deg;/&ndash;45&deg; directions transferred more than 90% of the impact energy back to the impactor because of the lamination of fibers in the orthogonal directions. Furthermore, the specimens that underwent complete damage in the impact tests were subjected to the lock-in method and showed internal delamination and cut fibers. With the finite elements analysis, the damage of each ply could be observed. Moreover, the temperature differences in the residual compression tests were not significant.

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