scholarly journals Effects of Bedding Geometry and Cementation Strength on Shale Tensile Strength Based on Discrete Element Method

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiong Wang ◽  
Yang Wang ◽  
Liu Yang ◽  
Tianquan Chang ◽  
Qingping Jiang
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Softening Effect ◽  
Strength Based ◽  
Increasing Trend ◽  
Simulation Results ◽  
Set Up ◽  
Brazilian Splitting ◽  
Line Crack

To study the effects of anisotropy and heterogeneity on the shale failure mode and tensile strength, Brazilian splitting tests were performed from both directions of the bedding and layer thickness. Layers containing different bedding and loading angles and layer thicknesses were obtained separately. The results show that, at 0° and 90° angles, the shale cracks grow “linearly”; at 15°, the shale cracks have “arc type” growth; and at 30°–75°, the shale-splitting displays “broken line” crack propagation. The tensile strength from 0° to 90° exhibits an increasing trend. Water has a significant softening effect on the tensile strength of shale—the higher the water content, the lower the tensile strength. In addition, a 3DEC numerical simulation was used to simulate the tests, establishing shale specimen particles with random blocks. In the shale disc, uneven parallel bedding and uniform parallel bedding were set up with different loading angles and layer thicknesses to generate simulated stress-displacement curves, and the effect of layering on shale cleavage was analyzed from a mesoscopic perspective. The tensile strength of shale with uniform parallel bedding was found to be higher under the same conditions, which is consistent with the experimental results. By comparing the experimental and simulation results, from both the macro- and mesoperspectives, the Brazilian splitting crack growth of shale is affected by bedding, displaying a process from disorder to order. This study is of great significance for further exploration of the mechanical properties of shale under loading failure.

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

scholarly journals An Investigation of Dynamic Responses and Head Injuries of Standing Subway Passengers during Collisions

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Yong Peng ◽  
Tuo Xu ◽  
Lin Hou ◽  
Chaojie Fan ◽  
Wei Zhou
Keyword(s):  
Numerical Simulation ◽  
Head Injury ◽  
Head Injuries ◽  
Dynamic Responses ◽  
Passive Safety ◽  
Friction Coefficients ◽  
Safety Design ◽  
Parametric Studies ◽  
Simulation Results ◽  
Set Up

With the development of the subway and the pressing demand of environmentally friendly transportation, more and more people travel by subway. In recent decades, the issues about passenger passive safety on the train have received extensive attention. In this research, the head injury of a standing passenger in the subway is investigated. Three MADYMO models of the different standing passenger postures, defined as baseline scenarios, are numerically set up. HIC15values of passengers with different postures are gained by systematic parametric studies. The injury numerical simulation results of various scenarios with different friction coefficients, collision acceleration, standing angle, horizontal handrail height, and ring handrail height are analyzed. Results show that the horizontal handrail provides better protection in the three different standing passenger postures. Different friction coefficients and the standing angle have great impact on the head injuries of passengers in three different scenarios. The handrail height also has some effects on head injury of passengers with different standing postures, so it is necessary to be considered when designing the interior layout of the subway. This study may provide guidance for the safety design of the subway and some advices for standing subway passengers.

Research on the Numerical Simulation of Silting in Floodplain and Scouting in Main Channel of Over-Bank Flooding in the Lower Yellow River

2011 ◽  
Vol 255-260 ◽  
pp. 3692-3696
Author(s):  
Xiao Lei Zhang ◽  
Dong Po Sun ◽  
Feng Ran Zhang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Yellow River ◽  
Main Channel ◽  
River Channel ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Water And Sediment ◽  
Simulation Results ◽  
Set Up

The 2-D water and sediment mathematical model which reflects silting in floodplain and scouting in main channel of over-bank flooding in the Lower Yellow River has been set up in this paper. Through carrying on 2-D water and sediment numerical simulation of the “96.8” typical flood, the author studied influence of over-bank flooding on flood travel and transverse exchange. The primary simulation results show that, adopting the over-bank flooding for silting in floodplain and scouting in main channel effectively guaranteed and expanded transverse exchange between floodplain and main channel and maintained the river channel vigor. This can relieve “secondary suspended river” states in the Low Yellow River to a certain extent; at the same time, the different magnitudes of over-bank floods have different effect of silting in floodplain and scouting in main channel.

scholarly journals Mechanical Properties of Tensile Strength of ITB Graft, a Promising Graft for Labral Reconstruction of the Hip

2020 ◽  
Vol 8 (5_suppl5) ◽  
pp. 2325967120S0011
Author(s):  
F Mahda ◽  
DR Sasetyo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Labral Repair ◽  
Iliotibial Band ◽  
Test Apparatus ◽  
Strength Based ◽  
Hydraulic Servo ◽  
Strength Curve ◽  
Male Sex ◽  
Sigmoid Shape

Introduction: Labral repair gives good results on damage in the labral area of the hip, but in cases with extensive labral damage, labral repair is less effective, reconstruction of labral is needed, recently labral reconstruction has been done using the Iliotibial band (ITB), but no one has measured the tensile strength of the ITB. this study intends to measure the ITB tensile strength based on diameter. Methode: This is an experimental research, the sample was taken from 8 cadaveric, consisted of 6 cadavercic male sex and 2 cadaveric female sex, the youngest cadaveric age was 25 years and the oldest 63 years with an average age of 47 years. Each cadaver was treated by taking ITB, The ITB were then measured by applying the Hydraulic Servo Pulser tensile test apparatus. ITB was rolled oval and tied with an unabsorbed polyster suture, the ITB which was oval shaped and had been tied with an unabsorbed polyster suture then measured its diameter from 4mm, 5mm, 6mm, 7mm, to 8mm. Samples that have been prepared are measured using a tensile strength gauge to assess ITB tensile strength ranging from 4mm, 5mm, 6mm, 7mm, to 8mm. Results: ITB’s tensile strength curve is sigmoid shape , the average tensile strength for all samples is 647 Psi. The larger the sample diameter, the greater the tensile strength it has. The largest tensile strength is obtained in 8 mm diameter, and the smallest tensile strength is obtained in 4 mm diameter. Conclusion: ITB is a promising autograft and can be used as an ingredient for the reconstruction of labral.

Metallurgical Evolutions in Hot Forging of Dual Phase Titanium Alloys: Numerical Simulation and Experiments

2015 ◽  
Vol 651-653 ◽  
pp. 225-230 ◽  
Author(s):  
Antonino Ducato ◽  
Gianluca Buffa ◽  
Antonello Astarita ◽  
Antonino Squillace ◽  
Livan Fratini ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Titanium Alloys ◽  
Case Studies ◽  
Hot Forging ◽  
Fe Model ◽  
Dual Phase ◽  
Model Output ◽  
Forged Parts ◽  
Set Up

Titanium forging has been encountering a growing interest in the scientific and industrial communities because of the distinct advantages it provides with respect to machining, in terms of both mechanical properties of the product and material waste, thus significantly reducing the Buy to Fly ratio. In the paper, a numerical FE model, based on a tri-coupled approach and able to predict the microstructural evolutions of the workpiece during the process, is developed and set up. Calculated results are compared to experiments for a few industrial case studies. The final phases distribution in the forged parts is experimentally measured and compared to the FE model output finding satisfying overlapping.

scholarly journals Study on Mechanical Properties of Submunition’s Ribbon Straightening Section

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Dong-ze Qin ◽  
Wei Zhang ◽  
Shu-Yun Zhang ◽  
Tian-Ji Guo ◽  
Shui-Yuan Pei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Force ◽  
Physical Structure ◽  
Simulation Software ◽  
Tension Test ◽  
Response Characteristics ◽  
Experimental Scheme ◽  
Drop Velocity ◽  
Simulation Results

The humanitarian damage caused by the unexploded submunitions is one of the hot issues of concern to the international community at present. A portion of the submunition that did not explode was caused by a break at the connection between the ribbon riveting and the fuze. According to the physical structure of the submunition and the trajectory into which it was ejected, we analyzed the forces of the submunition in flight, deduced the related mathematical models, and clarify the key elements of the mechanics. In this paper, the commercial simulation software was used to calculate the mechanical properties of the ribbon. And the variation regularity between drop velocity and straightening force of ribbon are revealed. And the response characteristics of different material ribbon with different sizes of riveting holes and riveting joints under tensile action were simulated. The simulation results show that, in the trajectory environment with 30 m/s~55 m/s typical stream speed, the tensile force of the ribbon is less than 300 N, and the application concentration of the connecting parts of the riveting joint and the ribbon will not cause the failure of the kevlar ribbon, but it will cause the failure of the nylon ribbon. In order to verify the variation of the tension of kevlar ribbons in different trajectory environments, we designed the experimental scheme of tension test of the ribbon straightening section of submunition and conducted experiments. Experimental results and numerical simulation results revealed the same law. This paper provides effective technical support for solving the problem of unexploded submunitions.

scholarly journals Influence of Heating on Tensile Physical-Mechanical Properties of Granite

2019 ◽  
Vol 38 (2019) ◽  
pp. 505-515 ◽  
Author(s):  
Xinyu Fang ◽  
Jinyu Xu ◽  
Shi Liu ◽  
Haoyu Wang
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Longitudinal Wave ◽  
Constant Temperature ◽  
Room Temperature ◽  
Laboratory Experiments ◽  
Turning Point ◽  
Longitudinal Wave Velocity ◽  
Granite Samples

AbstractHeating procedures dramatically influence the physical-mechanical properties of rock. In this paper, via both numerical simulation and laboratory experiments, we examine the influence of constant temperature period (CTP, from 0.5 to 5 h) and predetermined temperature (PDT, from room temperature to 1,000℃) on the tensile mechanical properties of the Qinling granite, China. Results indicate that: CTP has a significant impact on the tensile mechanical properties of granite. For different PDTs, the density, longitudinal wave velocity (LWV) and tensile strength (TS) of granite decrease with increasing CTP. When CTP reaches the constant temperature turning-point (CTT), heating has fully affected the granite samples. The variation in LWV and TS versus temperature can be divided into four stages: 25–200℃, 200–600℃, 600–800℃ and 800–1,000℃. LWV and TS are negatively related to temperature and are more sensitive to temperature at higher PDTs. In addition, TS is more sensitive to temperature than LWV when PDT increases. The effects of CTP and PDT on LWV are similar to that of TS. Since the measurement of LWV is lossless, researchers can safely determine the appropriate CTP or CTT for any PDT and predict the tensile mechanical properties of rock by LWV analysis.

Effect of Dies Temperature on Mechanical Properties of Hot Stamping Square-Cup Part for Ultra High Strength Steel

2010 ◽  
Vol 129-131 ◽  
pp. 390-394
Author(s):  
Cheng Xi Lei ◽  
Zhong Wen Xing ◽  
Hong Ya Fu
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Hot Stamping ◽  
High Strength ◽  
Hot Forming ◽  
Forming Process ◽  
Stamping Process ◽  
Ultra High Strength Steel ◽  
Mechanical Properties Testing ◽  
Simulation Results

The numerical simulation of hot-stamping process was carried out for UHSS square-cup parts, and the influence of dies temperature on the hot-stamping process was anlysised. Besides, through the microstructure analysis and mechanical properties testing of the formed parts, effects of dies temperature on microstructures and mechanical properties of hot-stamping square-cup parts were obtained. The experiment and simulation results showed that the mechanical properties of the UHSS are strongly dependent on the temperature, so the dies temperature is one of the most important parameters that have to be taken into account in designing the hot-forming dies and the hot-forming process.

Design and Simulation Research on Mechanical Ventilation System for Small Underground Granary

2014 ◽  
Vol 875-877 ◽  
pp. 2148-2151
Author(s):  
Hai Hong Zhang ◽  
Zhong Ying Wang ◽  
Qiang Liu ◽  
Peng Fei Ma
Keyword(s):  
Numerical Simulation ◽  
Mechanical Ventilation ◽  
Pressure Field ◽  
Ventilation System ◽  
Simulation Research ◽  
New Type ◽  
Simulation Results ◽  
Dynamic Numerical Simulation ◽  
Set Up ◽  
Better Than

The mechanical ventilation system of new type underground granary was designed and three wind pipe models with different length were investigated in this paper. Dynamic numerical simulation was applied for evaluating the cooling effect of mechanical ventilation of the granary. The simulation results, including temperature field, flow field and pressure field results, show that the cone shaped base of grain granary is better than flat shaped base. It is an optimal project that the main wind pipe opens with mesh only in the bottom. In addition, four vertical guide plates were set up around the main wind pipe, which have the function of saving energy and reducing consumption.

scholarly journals ANALISIS MATERIAL KOMPOSIT BERBASIS SERAT PELEPAH KELAPA SAWIT DAN MATRIKS POLYPROPYLENE SEBAGAI BAHAN PEMBUATAN BUMPER MOBIL

2019 ◽  
Vol 2 (2) ◽  
pp. 15
Author(s):  
Rizal Hanifi ◽  
Gebyar Dewangga ◽  
Kardiman Kasiadi ◽  
Eri Widianto
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Physical Properties ◽  
Volume Fraction ◽  
Test Results ◽  
Hot Press ◽  
Static Test ◽  
Failure Simulation ◽  
Simulation Results

Research has been carried out on the analysis of mechanical properties and simulation of composite failure of oil palm midrib fiber polypropylene matrix as car bumpers. This research is expected to provide information on the results of testing the mechanical properties and physical properties and to find out the results of failure simulation in stress analysis based on static test using Inventor Professional 2015 software. Composite boards are made using the hot press method with three variations volume fraction is 20% fiber: 80% matrix, 30% fiber: 70% matrix and 40% fiber: 60% matrix. Characterization of composite physical properties in the form of density, swelling, and water uptake while mechanical properties in the form of tensile testing. Composite physical test results showed that composites made according to JIS A5908 (2003) composite tensile test results showed that the maximum tensile strength obtained at the volume fraction of 40% fiber: 60% matrix with a value of 21.106 MPa, followed by a decrease in tensile strength in volume fraction 30% fiber: 70% matrix and 20% fiber: 80% matrix. Increased tensile strength due to direct orientation of fibers and the addition of fiber composition. Composites are still worth making bumper because the value of tensile strength is no less than the standard bumper which is 8,09 MPa. Next, failure simulation results based on a static test uses three variations of speed, namely 60 km/hr, 80 km/hr and 100 km/hr. The failure simulation results based on the static test of the three speed variations show the value of the von misses stress below the yield strength of the material, then the displacement value that occurs is small and the value of the safety factor produced is above one. From the results of the analysis of composite testing, it shows that the composite has the potential to be a car bumper material.Telah dilakukan penelitian tentang analisis sifat mekanik dan simulasi kegagalan komposit serat pelepah kelapa sawit matriks polypropylene sebagai bumper mobil. Penelitian ini diharapkan dapat memberi informasi hasil pengujian sifat mekanik dan sifat fisis serta mengetahui hasil simulasi kegagalan dalam stress analysis berdasarkan static test menggunakan software Inventor Professional 2015. Papan komposit dibuat menggunakan metode hot press dengan tiga variasi fraksi volume yaitu 20% serat: 80% matriks, 30% serat: 70% matriks dan 40% serat: 60% matriks. Karakterisasi sifat fisis komposit berupa densitas, swelling, dan serapan air sedangkan sifat mekanik berupa pengujian tarik. Hasil pengujian fisis komposit menunjukkan bahwa komposit yang dibuat sesuai dengan klasifikasi JIS A5908. Hasil pengujian tarik komposit menunjukkan bahwa nilai kekuatan tarik maksimal yang paling besar diperoleh pada fraksi volume 40% serat: 60% matriks dengan nilai 21,106 MPa, diikuti penurunan kekuatan tarik pada fraksi volume 30% serat: 70% matriks dan 20% serat: 80% matriks. Meningkatnya kekuatan tarik dikarenakan orientasi serat searah dan penambahan komposisi serat. Komposit masih layak dibuat bumper karena nilai kekuatan tariknya tidak kurang dari standar bumper yaitu 8,09 MPa. Selanjunya, hasil simulasi kegagalan berdasarkan static test menggunakan tiga variasi kecepatan yaitu 60 km/jam, 80 km/jam dan 100 km/jam. Hasil simulasi kegagalan berdasarkan static test dari ketiga variasi kecepatan tersebut menunjukkan nilai von misses stress dibawah nilai yield strength yang dimiliki material, kemudian nilai displacement yang terjadi kecil serta nilai safety factor yang dihasilkan yaitu di atas satu. Dari hasil analisis pengujian komposit tersebut menunjukkan bahwa komposit berpotensi sebagai material bumper mobil

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