scholarly journals Assessment of stratification of the breeds of the underground cavity roof

2021 ◽  
Vol 258 ◽  
pp. 04009
Author(s):  
Tamara Makeeva ◽  
Vitaly Trofimov
Keyword(s):  
Tensile Strength ◽  
Crack Length ◽  
Iterative Procedure ◽  
Boundary Elements ◽  
Underground Cavity ◽  
Vertical Pipe ◽  
Layer Material ◽  
Method Of Boundary Elements ◽  
Horizontal Cavity ◽  
Mechanism Of Failure

Authors of the research consider the approach to the assessment of possibility of formation of stratification and shift cracks in the roof of extended horizontal cavity, based on the method of boundary elements. The algorithm implements the iterative procedure of variation of the formed crack length with control of tension in its tip. At the same time, the angle of the crack coasts closing is defined by the tensile strength of the layer material. The crack with smooth closing of coasts is formed in case of equality to zero this durability. The mechanism of failure forming over the developed space with vertical pipe type walls is considered. The results received by the authors, can be useful as the offered approach allows to model the destructions localization in the massif of rocks, location and sizes of the arising cracks of stretching and shift if there are strength defects in the massif

APPLICATION OF OIL PALM EMPTY FRUIT BUNCH FIBERS IN STRENGTH IMPROVEMENT AS A FIBER REINFORCED CONCRETE

2017 ◽  
Vol 25 (3) ◽  
pp. 161-170
Author(s):  
Henny Lydiasari ◽  
Ari Yusman Manalu ◽  
Rahmi Karolina
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Crack Length ◽  
Oil Palm ◽  
Fiber Reinforced Concrete ◽  
Structural Concrete ◽  
Empty Fruit Bunches ◽  
Construction Products ◽  
By Products ◽  
Strength Improvement

The potency of oil palm empty fruit bunches (OPEFB) fibers as one of the by-products of processing oil palm is increasing significantly so that proper management is needed in reducing environmental impact. One of the utilization of OPEFB fibers is as a substitution material in construction which usually the material is derived from non-renewable mining materials so that the number is increasingly limited. Therefore, it is necessary to study to know the performance of OPEFB fiber in making construction products especially concrete. In this case, the experiment was conducted using experimental method with variation of fiber addition by 0%, 10%, 15%, 20%, 25%, and 30%. Each specimen was tested by weight, slump value, compressive strength, tensile strength, elasticity and crack length. As the results, the variation of fibers addition by 10%, decrease of slump value is 7%, concrete weight is 3% and crack length is 8% while increase of the compressive strength is 2.7% and the modulus of elasticity is 33.3% but its tensile strength decreased insignificantly by 0.05% . Furthermore, the addition of fibers above 10% to 30% decreased compressive strength is still below 10% and tensile strength below 2% while the weight of concrete, slump value and crack length decreased. Therefore, the addition of 10% can replace the performance of concrete without fiber but the addition of above 10% can still be used on non-structural concrete.

scholarly journals Calculation of plate-beam systems by method of boundary elements

2018 ◽  
Vol 7 (2.23) ◽  
pp. 238 ◽  
Author(s):  
Mykola Surianinov ◽  
Oleksii Shyliaiev
Keyword(s):  
Finite Elements ◽  
Fundamental System ◽  
Boundary Elements ◽  
Algebraic Equations ◽  
Contact Conditions ◽  
Small System ◽  
Beam System ◽  
Linear Algebraic Equations ◽  
Method Of Boundary Elements ◽  
Load Vector

The approach to calculation of plate-beam systems by numerical and analytical method of boundary elements is proposed. The method consists in construction in analytical way a fundamental system of solutions, the Green’s function and external load vector for the problem under consideration. Small system of linear algebraic equations to be solved numerically is constructed to take into account the boundary conditions or contact conditions between separate modules.The series of plate-beam system calculations by methods of boundary elements and finite elements at different geometric parameters of plate was performed to assess the limits of applicability of developed theory. The comparison of 45 variants calculations by both methods is shown.  

scholarly journals The solution of the plane problem of the theory of elasticity by the boundary elements method

2020 ◽  
Vol 211 ◽  
pp. 02021
Author(s):  
Mykola Surianinov ◽  
Yurii Krutii ◽  
Anatolii Kovrov ◽  
Vladimir Osadchiy
Keyword(s):  
Plane Problem ◽  
Boundary Elements ◽  
Theory Of Elasticity ◽  
Element Analysis ◽  
One Dimensional ◽  
Method Of Boundary Elements ◽  
Boundary Elements Method ◽  
Numerical Analytical Method ◽  
The Green Function ◽  
The One

An approach to solving the biharmonic equation of the plane problem of the theory of elasticity by the numerical-analytical method of boundary elements is developed. The reduction of the two-dimensional problem to the one-dimensional one was carried out by the KantorovichVlasov method. Systems of fundamental orthonormal functions and the Green function are constructed without any restrictions on the nature of the boundary conditions. A numerical example of solving a plane problem by the boundary element method for a rectangular plate is considered. The results are compared with the data of finite element analysis in the ANSYS program and those obtained by A.V. Aleksandrov.

Causes of Flexor Tendon Repair Failures in Two Common Repair Techniques: A Cadaver Study

2016 ◽  
Vol 21 (03) ◽  
pp. 333-338 ◽  
Author(s):  
Raakhi Mistry ◽  
Michael John McCleave ◽  
John Codrington
Keyword(s):  
Tensile Strength ◽  
Flexor Tendon ◽  
Tendon Repair ◽  
Cadaver Study ◽  
Flexor Tendon Repair ◽  
Maximum Tensile Strength ◽  
Pull Out ◽  
Mechanism Of Failure ◽  
Suture Failure ◽  
Repair Techniques

Background: Flexor tendon repair failures have primarily been attributed to either core suture rupture or core suture pull out. Recent studies have suggested that knot unravelling may also cause failure of a tendon repair. The aim of this study was to investigate the causes of core suture failure in two types of common flexor tendon repairs. Methods: Twenty four cadaver tendons were divided into three groups of eight. Each group tested a specific flexor tendon repair. The repairs tested included an Adelaide repair using 4/0 Ethibond (Ethicon), an Adelaide repair using 4/0 Fiberwire (Arthrex) and the Tsai repair with 4/0 Fiberloop (Arthrex). The repaired tendons were pull-tested to failure. The mechanism of failure, maximum tensile strength and 2 mm gap force were recorded. Results: The predominant mode of failure was by the knot unravelling. This occurred in 50-88% of the tendon repairs. The sequence of failure was initiated with gapping at the repair site followed by failure of the epitendinous suture. Next the core suture knot unravels. Once the knot unravels, the suture thread slips out of the tendon resulting in the repair failure. Failures due to knot slippage occurred at a lower maximum tensile strength in Ethibond and Fiberloop sutures than failure due to core rupture or pull out. However, given the small number of tendons tested, this result was not significant. Conclusions: This study has clearly demonstrated one of the main causes of flexor tendon repair failure in two common repair techniques is knot unravelling.

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