Influence of Temperature on Ductile-Fragile Behavior

2014 ◽  
Vol 802 ◽  
pp. 383-387
Author(s):  
C.A. Silva ◽  
R.C.R. Nascimento ◽  
M.S. Martins ◽  
M.C.S. Freitas
Keyword(s):  
Fracture Mode ◽  
Impact Energy ◽  
Impact Test ◽  
Evaluation Criteria ◽  
Test Body ◽  
Gravitational Potential Energy ◽  
Machine Component ◽  
Whole Process ◽  
Before And After ◽  
The Impact

The article to be presented will cover the whole process done in a fracture test for impact, taking into account the thermal treatment of the sample to be studied. The main objective of this article is to observe, verify, analyze and understand how the temperature difference of several samples influences the type and appearance of the fracture. The impact test have a great importance in industry, is through this that you can verify that the material is ideal for application in the production of equipment and vehicles that operate in high or low temperatures. The evaluation criteria of this trial are the energy absorbed by the sample, and the percentage of its characteristic lateral extension, and the percentage of fracture, ductile or fragile, and corresponding to a ductile fracture mode, in which the test at higher temperatures, the impact energy is relatively large, and fragile fracture mode, being one that as the temperature decreased, the impact energy will suffer decline. The most important result of the impact test is the measure of the energy absorbed by the test body to deform and break, measured by the variance of the gravitational potential energy of the hammer (machine component of the impact test) before and after impact. Therefore, providing the conclusion that the smaller the energy absorbed by the sample, more fragile it is depending on the temperature applied.

Effects of Annealing Process on Mechanical Properties of Weather-Resistant Steel Welding Joints

2018 ◽  
Vol 777 ◽  
pp. 397-401
Author(s):  
Qiang Zhang ◽  
Zhe Wu ◽  
Hong Wu Li
Keyword(s):  
Mechanical Properties ◽  
Impact Energy ◽  
Welded Joints ◽  
Impact Test ◽  
Resistant Steel ◽  
Test Results ◽  
Before And After ◽  
Welding Joints ◽  
Weld Area ◽  
The Impact

In this paper, the mechanical properties of Q355NH resistant steel welded joints are studied. Through the analysis of mechanical properties of welded joints, the results showed that the tensile strength of the welded joints decreased after annealing and the elongation increased. The impact test results of tensile specimens before and after annealing showed that the impact energy of the weld area increased greatly after annealing, while the impact energy of the heat affected zone changed little. Furtherly, fatigue strength of specimens before and after annealing was compared, and the results showed that under the condition of high cycle fatigue, the un-annealed specimens were broken and the fracture position was located on the parent metal, whereas the annealed specimens did not break.

scholarly journals Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  
Keyword(s):  
Impact Energy ◽  
Impact Test ◽  
Impact Resistance ◽  
Protective Layer ◽  
High Strength ◽  
Steel Plates ◽  
Corrugated Plates ◽  
Shelter Construction ◽  
The Impact ◽  
Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

scholarly journals Body Composition Changes in Gastric Cancer Patients during Preoperative FLOT Therapy: Preliminary Results of an Italian Cohort Study

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 960
Author(s):  
Emanuele Rinninella ◽  
Antonia Strippoli ◽  
Marco Cintoni ◽  
Pauline Raoul ◽  
Raffaella Vivolo ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Body Composition ◽  
Tumor Regression ◽  
Evaluation Criteria ◽  
Tumor Regression Grade ◽  
Skeletal Muscle Index ◽  
Before And After ◽  
Gastric Cancer Patients ◽  
The Impact ◽  
Composition Changes

Background: The impact of the new chemotherapy, fluorouracil plus leucovorin, oxaliplatin, and docetaxel (FLOT) on body composition in gastric cancer (GC) patients remains unknown. We assessed body composition changes of GC patients receiving the FLOT regimen and their impact on treatment outcomes. Methods: Preoperative pre- and post-FLOT computed tomography (CT) scans of advanced GC patients were studied. Lumbar skeletal muscle index (SMI) and adipose indices were calculated before and after FLOT. Results: A total of 26 patients were identified between April 2019 and January 2020. Nineteen patients were sarcopenic at diagnosis. The mean BMI decreased (from 24.4 ± 3.7 to 22.6 ± 3.1; p < 0.0001) as well as the SMI (from 48.74 ± 9.76 to 46.52 ± 9.98; p = 0.009) and visceral adipose index (VAI) (from 49.04 ± 31.06 to 41.99 ± 23.91; p = 0.004) during preoperative FLOT therapy. BMI, SMI, and VAI variations were not associated with toxicity, Response Evaluation Criteria in Solid Tumors (RECIST), response, delay and completion of perioperative FLOT chemotherapy, and the execution of gastrectomy; a decrease of SMI ≥ 5% was associated with a higher Mandard tumor regression grade (p = 0.01). Conclusions: Almost three-quarters (73.1%) of GC patients were sarcopenic at diagnosis. Preoperative FLOT was associated with a further reduction in SMI, BMI, and VAI. These changes were not associated with short-term outcomes.

scholarly journals The Effect of Layers and Bullet Type on Impact Properties of Glass Fibre Reinforced Polymer (GFRP) Using a Single Stage Gas Gun (SSGG)

2014 ◽  
Vol 564 ◽  
pp. 428-433 ◽  
Author(s):  
S.N.A. Safri ◽  
Mohamed Thariq Hameed Sultan ◽  
N. Razali ◽  
Shahnor Basri ◽  
Noorfaizal Yidris ◽  
...  
Keyword(s):  
Impact Energy ◽  
Glass Fibre ◽  
Impact Test ◽  
Single Stage ◽  
Gas Gun ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
The Impact

The purpose of this work is to study the best number of layer with the higher impact energy using Glass Fibre Reinforced Polymer (GFRP). The number of layers used in this study was 25, 33, 41, and 49. The impact test was performed using Single Stage Gas Gun (SSGG) for each layers given above with different bullets such as blunt, hemispherical and conical bullets. The gas gun pressure was set to 5, 10, 15 and 20 bar. All of the signals captured from the impact test were recorded using a ballistic data acquisition system. The correlation between the impact energy in terms of number of layer and type of bullet from this test are presented and discussed. It can be summarise that as the number of layer increases, impact energy also increases. In addition, from the results, it was observed that by using different types of bullets (blunt, hemispherical, conical), there is only a slight difference in values of energy absorbed by the specimen.

scholarly journals Finite Element Analysis of Impact Energy on Spur Gear

2018 ◽  
Vol 225 ◽  
pp. 06011 ◽  
Author(s):  
Ismail Ali Bin Abdul Aziz ◽  
Daing Mohamad Nafiz Bin Daing Idris ◽  
Mohd Hasnun Arif Bin Hassan ◽  
Mohamad Firdaus Bin Basrawi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Impact Energy ◽  
High Speed ◽  
Impact Test ◽  
Impact Load ◽  
Gear Tooth ◽  
Test Equipment ◽  
Element Analysis ◽  
The Impact

In high-speed gear drive and power transmission, system impact failure mode always occurs due to the sudden impact and shock loading during the system in running. Therefore, study on the amount of impact energy that can be absorbed by a gear is vital. Impact test equipment has been designed and modelled for the purpose to study the impact energy on gear tooth. This paper mainly focused on Finite Element Analysis (FEA) of impact energy that occurred during simulation involving the impact test equipment modelling. The simulation was conducted using Abaqus software on critical parts of the test equipment to simulate the impact event and generate impact data for analysis. The load cell in the model was assumed to be free fall at a certain height which gives impact load to the test gear. Three different type of material for the test gear were set up in this simulation. Results from the simulation show that each material possesses different impact energy characteristic. Impact energy values increased along with the height of load drop. AISI 1040 were found to be the toughest material at 3.0m drop that could withstand up to 44.87N.m of impact energy. These data will be used to validate data in physical experiments in further study.

scholarly journals Degradation of Roller-Compacted Concrete Subjected to Freeze-Thaw Cycles and Immersion in Potassium Acetate Solution

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Wuman Zhang ◽  
Jingsong Zhang ◽  
Shuhang Chen ◽  
Sheng Gong
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Compressive Strength ◽  
Impact Energy ◽  
Impact Test ◽  
Potassium Acetate ◽  
Acetate Solution ◽  
Freeze Thaw ◽  
Roller Compacted Concrete ◽  
The Impact

Two sets of roller-compacted concrete (RCC) samples cured for 28 days were subjected to freeze-thaw (F-T) cycles and immersion in laboratory conditions. F-T cycles in water and water-potassium acetate solution (50% by weight) were carried out and followed by the flexural impact test. The weight loss, the dynamic elastic modulus (Ed), the mechanical properties, and the residual strain of RCC were measured. The impact energy was calculated based on the final number of the impact test. The results show that the effect of F-T cycles in KAc solution on the weight loss and Ed of RCC is slight. Ed, the compressive strength, and the flexural strength of RCC with 250 F-T cycles in KAc solution decrease by 3.8%, 23%, and 36%, respectively. The content (by weight) of K+ at the same depth of RCC specimens increases with the increase of F-T cycles. The impact energy of RCC specimens subjected to 250 F-T cycles in KAc solution decreases by nearly 30%. Microcracks occur and increase with the increase of F-T cycles in KAc solution. The compressive strength of RCC immersed in KAc solution decreases by 18.8% and 32.8% after 6 and 12 months. More attention should be paid to using KAc in practical engineering because both the freeze-thaw cycles and the complete immersion in KAc solution damage the mechanical properties of RCC.

scholarly journals Effect of Heat Treatment on Microstructure and Impact Toughness of Ti-6Al-4V Manufactured by Selective Laser Melting Process

2017 ◽  
Vol 62 (2) ◽  
pp. 1341-1346 ◽  
Author(s):  
K.-A. Lee ◽  
Y.-K. Kim ◽  
J.-H. Yu ◽  
S.-H. Park ◽  
M.-C. Kim
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Selective Laser Melting ◽  
Impact Energy ◽  
Charpy Impact ◽  
Melting Process ◽  
Laser Melting ◽  
Average Impact ◽  
Before And After ◽  
The Impact

AbstractThis study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-βgrain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment,αandβphase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.

Dynamic Response of Hammer Impacting Pile under Gravity Field

2014 ◽  
Vol 610 ◽  
pp. 65-69
Author(s):  
Dong Hua Chen ◽  
Li Quan Wang
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Gravity Field ◽  
Impact Energy ◽  
Model Simulation ◽  
Gravitational Potential Energy ◽  
Impact System ◽  
Pile Cap ◽  
Hammer Impact ◽  
The Impact

Pile hammer impact system is composed of hammer, pile cap and pile. Gravity field will produce uneven stress in the pile which is placed on a fixed rigid plane, and gravitational potential energy will increase the impact energy which is inputted to the pile during the impact process. These will influence dynamic response of collision process between pile hammer and pile. In this paper, a gravity field factor was added in the Simth difference equations which are based on One-dimensional Wave Equation. The numerical model of pile hammer impact system was established. A program was written to implement the numerical model. Simulation results indicated that the duration of collision, the peak and stable value of impact force and the effective impact energy would be affected by the gravity field.

Evaluation of Sliding Behavior of Simple Structures for Oblique Collision

2014 ◽  
Vol 566 ◽  
pp. 611-616
Author(s):  
Takeru Watanabe ◽  
Naoya Nishimura ◽  
Hiroka Watanabe ◽  
Syouta Nakadate ◽  
Katsuhiko Murase
Keyword(s):  
Contact Surface ◽  
High Speed ◽  
Simple Structure ◽  
Impact Test ◽  
Testing Machine ◽  
Impact Testing ◽  
Oblique Collision ◽  
Before And After ◽  
Collapse Behavior ◽  
The Impact

When a simple structure collides with inclined barrier, behavior and deformation of the structure after impact are different in the case in which the structure slides on a contact surface or the case in which it does not slide. In order to investigate the structural collapse behavior for oblique collided structure, therefore, it is important to clarify the sliding behavior of the structure on the contact surface. The sliding behavior of the structure during collision was estimated according to theoretically obtained the equation considering the equilibrium of change in the momentum and the impulse before and after the collision. For evaluating the sliding behavior of the simple structure, the impact test by the drop type impact testing machine was carried out to collide with inclined barrier. In the impact test, the circular plate of 60 mm diameter and 10 mm thickness was used as the simple structure, and impacted with various collision velocities (range from 2 to 6 m/s). The sliding behavior of the simple structure at the collided surface was observed by high speed camera, and evaluated by the image analysis. The theoretical result was compared to evaluate with experimental results.

scholarly journals Study impact toughness on polyester matrix composite fiberglass reinforced Musa acuminata stem fibers as raw material of rear bumper vehicle

2020 ◽  
Vol 5 (3) ◽  
pp. 094-098
Author(s):  
Sujita Darmo Darmo ◽  
Rudy Sutanto Sutanto
Keyword(s):  
Impact Toughness ◽  
Matrix Composite ◽  
Impact Energy ◽  
Impact Test ◽  
Volume Fraction ◽  
Natural Fibers ◽  
Musa Acuminata ◽  
Raw Material ◽  
Polyester Matrix ◽  
The Impact

The use of natural fibers as composite reinforcement has various advantages, including as substitute for artificial fiber, low price, able to reduce sound, environmentally friendly, has low density, good fit and ability to absorb impact energy, making it possible to use it as a vehicle accessory such as a rear bumper vehicle. This study aims to investigate the impact toughness performance of the fiberglass matrix composite polyester (FMCP) reinforced fiber Musa acuminata stem fiber (MASF), with a volume fraction of 5%, 10%, 15%, 20% and 25%. Polyester matrix type 157 is used BQTN and G3253T, MEKPO catalyst. The impact toughness test was carried out by using the charpy method impact test instrument, observing the microstructure of the occurrence of fracture by using scanning electron microscope (SEM). The composite impact test specimen was 12.7 thick mm refers to the ASTM D 256 standard, produced by the hand layup method. The most optimal volume fraction impact test at a volume fraction of 20% MASF: 80% Matrix, with an impact energy of 14.47 J, impact toughness 0.094 J/mm2. The results showed that the addition of MASF increased the impact toughness of the composite by 14.69% compared to composites 0.0122 J/mm2. Based on SEM observations, it can be seen that the 20% MASF volume fraction of the bonds between the matrix and the fibers are perfectly integrated. The results showed that the addition of MASF increased the impact toughness of the composite by 14.69% compared to composites 0.0122 J/mm2. However, if a volume fraction ratio above 20% MASF is used, the impact toughness is decreased.

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