Constitutive equations for reliable projectile penetration analysis into a concrete medium

2019 ◽  
Vol 11 (2) ◽  
pp. 159-184
Author(s):  
Vladimir R Feldgun ◽  
David Z Yankelevsky
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Equation Of State ◽  
Penetration Depth ◽  
Uniaxial Compressive Strength ◽  
Constitutive Equations ◽  
Concrete Strength ◽  
Time History ◽  
Non Linear ◽  
Concrete Target

This article analyzes the fundamental question of the mechanical properties representation in penetration analysis and its effect on the calculated results. Penetration analysis into a concrete target with a specified uniaxial compressive strength was carried out using different material models appearing in software libraries. These models determine the specific material equation of state and shear strength envelope related to the concrete uniaxial compressive strength. Different results were obtained for the same concrete strength. This proves that the unconfined compressive strength is not the governing parameter which determines the projectile penetration characteristics and that a large variation of results is obtained from different models. Analysis was then carried out on a case with documented constitutive properties of a concrete target that was penetrated by an instrumented projectile. The predicted penetration depth and the projectile deceleration time history were compared with the measured data, and very good correspondence was obtained. This proved that the specific properties of the penetrated medium should be incorporated in the analysis to properly predict the penetration event. The study then examined the commonly used approximation of a linearized equation of state and a linear Mohr–Coulomb model, replacing the true non-linear equations of state and the true non-linear shear strength dependence, and the linearized relationships’ effect on the analyzed results was assessed. A detailed study of the solution sensitivity to different parameters of the Mohr–Coulomb relationship then followed, and its effect on different penetration parameters (nose embedment duration, nose embedment velocity, penetration depth, peak deceleration, quasi-static deceleration) has been examined, to demonstrate how a perturbation in assumed concrete properties affects the solution of the penetration problem. The article illuminates the role of the constitutive equations on penetration analysis and the importance of the proper selection of the representative expressions and of their approximations.

scholarly journals Theoretical and Numerical Study of Shear Strength of Concrete Material

2020 ◽  
Vol 13 (5) ◽  
pp. 161-168
Author(s):  
Liu Jun ◽  
◽  
Xiang Yuzhou ◽  
Xiong Yucheng ◽  
Wu zusong ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Numerical Study ◽  
Concrete Strength ◽  
Strength Characteristics ◽  
Theoretical Formula ◽  
Concrete Material ◽  
Study Results ◽  
Concrete Materials ◽  
Mohr’S Circle

The shear strength of some concrete materials should be analyzed based on elastic-plastic theory in petroleum, water conservancy, tunnel engineering, and so on. The majority of researches concentrate mainly on the tensile and compressive strength of concretes, but few have studied the shear strength. Concrete materials have been increasingly applied broadly to geotechnical engineering. Thus, investigating the shear strength characteristics of concretes is of great importance. To study the characteristics of shear strength of concrete materials, the theoretical relationship between concrete’s compressive and shear strengths was discussed in the uniaxial, biaxial, and triaxial stress states. The concrete strength envelopes under the biaxial and uniaxial compressive strength were studied. Given the concrete shear strength, the overload method and the finite difference software FLAC3D were used to investigate the concrete failure modes and ultimate bearing capacities. Results show that the theoretical formula under the 3D stress-bearing condition is only applicable to the circumstance with equal compressive strengths under the biaxial and uniaxial conditions, which conforms to 3D Mohr’s circle theory. 3D Mohr’s circle theory is not totally applicable to concrete materials where the concrete compressive strength under the biaxial condition is larger than that under the uniaxial condition. Concrete material gains its shear strength 47 percent from its frictional force while the rest form cohesive force. The study results can provide a certain basis and reference for analyzing the shear strength characteristics of concrete materials.

scholarly journals Shear Strength of Reinforced Recycled Aggregate Concrete Corbels

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ahid Zuhair Hamoodi ◽  
Aqeel Hatem Chkheiwer ◽  
Jaffar Ahmed Kadim
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Failure Load ◽  
Concrete Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Depth Ratio ◽  
Failure Loads ◽  
Effective Depth

This paper is related to a laboratory program for the shear strength of reinforced concrete corbels (RCC) cast with or without recycled aggregate (RA) by investigating the main parameters affecting the corbels behavior including the replacement aggregate recycling ratio, fcu, and shear span to effective depth ratio a/d. Eight specimens were cast and tested. The obtained results were compared with ACI and EC2 codes. It is found that the ACI code and E2 code give sensibly conservative results when compared with the findings of the present work for all tested specimens regarding RA, concrete strength, and a/d. Also, the experimental results show that the presence of recycled aggregate decreases slightly both cracking and failure loads. Furthermore, the failure load development due to the effect of compressive strength is more effective with the presence of recycled aggregate, and the 50% ratio of RA was the suitable ratio in elaborate crack and failure loads. Finally, the reduction of the span-depth ratio (from 0.50 to 0.35) increases the crack and failure load by 8.1% and 20.2%, respectively, leading to confirm that the corbel strength is much sensitive to decreasing span-depth ratio compared to the associated deflections.

Application of several non-linear prediction tools for estimating uniaxial compressive strength of granitic rocks and comparison of their performances

2015 ◽  
Vol 32 (2) ◽  
pp. 189-206 ◽  
Author(s):  
Danial Jahed Armaghani ◽  
Edy Tonnizam Mohamad ◽  
Mohsen Hajihassani ◽  
Saffet Yagiz ◽  
Hossein Motaghedi
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Linear Prediction ◽  
Granitic Rocks ◽  
Prediction Tools ◽  
Non Linear

scholarly journals Experimental Investigation on Strength and Failure Characteristics of Cemented Paste Backfill

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhihong Zhang ◽  
Jiacheng Li
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Uniaxial Compressive Strength ◽  
Cement Content ◽  
Confining Pressure ◽  
Curing Temperature ◽  
Cemented Paste Backfill ◽  
Upward Trend ◽  
Paste Backfill ◽  
Curing Age

The strength characteristics of cemented paste backfill (CPB) in mining areas are key control factors for the safety assessment of overlying strata. A series of experiments about uniaxial compression and triaxial compression were carried out to study the influence of cement content of filling slurry, curing age, and curing temperature on strength behavior of CPB specimens. The failure mechanism and damage feature of CPB have been investigated. The results show the following: (1) The uniaxial compressive strength of CPB specimens exhibits an upward trend with the increase of cement content and curing age. When the cement content is high, the uniaxial compressive strength increases sharply with increasing curing age. (2) The cohesion of CPB specimens increases with the increase of cement content of filling slurry, curing age, and curing temperature. The cohesion of CPB specimens with curing age 7 days and 14 days increases linearly with increasing cement content. At the later stage of curing age, the strength growth of high cement content backfill is significantly greater than that of low cement content. The internal friction angle of the filling increases slightly with increasing filling cement content, curing age, and curing temperature. (3) The shear strength of CPB specimens at curing age 7 days exhibits an upward trend with the increase of confining pressure, while the shear strength at 14 days and 28 days curing age decreases slightly as the confining pressure increases. (4) With the increase of cement content in backfill, the brittleness increases significantly when the backfill is damaged. The failure mode of CPB specimens changes from monoclinic section shear failure to X-type failure with increasing curing age, and the failure process is divided into four stages: pore compaction, linear elastic deformation, plastic deformation, and post-peak failure.

PERILAKU STRUKTUR BAJA TIPE MRF DENGAN BEBAN LATERAL BERDASARKAN SNI 1726-2012 DAN METODE PERFORMANCE BASED PLASTIC DESIGN (PBPD)

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Nidiasari Jati Sunaryati Eem Ikhsan
Keyword(s):  
Pushover Analysis ◽  
Time History ◽  
Time History Analysis ◽  
Plastic Design ◽  
History Analysis ◽  
Non Linear ◽  
Static Pushover Analysis

Struktur rangka baja pemikul momen merupakan jenis struktur baja tahan gempa yang populer digunakan. Daktilitas struktur yang tinggi merupakan salah satu keunggulan struktur ini, sehingga mampu menahan deformasi inelastik yang besar. Dalam desain, penggunaan metode desain elastis berupa evaluasi non-linear static (Pushover analysis) maupun evaluasi non-linear analisis (Time History Analysis) masih digunakan sebagai dasar perencanaan meskipun perilaku struktur sebenarnya saat kondisi inelastik tidak dapat digambarkan dengan baik. Metode Performance-Based Plastic Design (PBPD) berkembang untuk melihat perilaku struktur sebenarnya dengan cara menetapkan terlebih dahulu simpangan dan mekanisme leleh struktur sehingga gaya geser dasar yang digunakan adalah sama dengan usaha yang dibutuhkan untuk mendorong struktur hingga tercapai simpangan yang telah direncanakan. Studi dilakukan terhadap struktur baja 5 lantai yang diberi beban gempa berdasarkan SNI 1726, 2012 dan berdasarkan metode PBPD. Hasil analisa menunjukkan bahwa struktur yang diberi gaya gempa berdasarkan metode PBPD mencapai simpangan maksimum sesuai simpangan rencana dan kinerja struktur yang dihasilkan lebih baik .

Determination of Concrete Cube Strength from Used Samples / Určení Krychelné Pevnosti Betonu U Použitých Zkušebních Trámců

2012 ◽  
Vol 12 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Oldřich Sucharda ◽  
David Mikolášek ◽  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Concrete Beams ◽  
Linear Analysis ◽  
Bending Tests ◽  
Cube Strength ◽  
Non Linear ◽  
Compressive Strength Of Concrete ◽  
Concrete Cube

Abstract This paper deals with the determination of compressive strength of concrete. Cubes, cylinders and re-used test beams were tested. The concrete beams were first subjected to three-point or fourpoint bending tests and then used for determination of the compressive strength of concrete. Some concrete beams were reinforced, while others had no reinforcement. Accuracy of the experiments and calculations was verified in a non-linear analysis.

PENGKAJIAN KEKUATAN BETON STRUKTUR JEMBATAN PASCA KEBAKARAN

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Strength Assessment ◽  
Concrete Testing

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.

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