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CONTENTS
Volume 11, Number 4, December 2022
 


Abstract
Disposal of industrial waste in cities where municipal authorities permitting higher floor area ratio coupled with increasing living standards, a lot of demolition waste is being generated. Its disposal is a challenge particularly in megacities where no landfills are available. The ever-increasing cost of building construction materials also necessitates consuming demolition wastes in a useful manner to save fresh natural raw materials. In the present work, the crushed waste glass is used in high-strength concrete as a partial replacement of fine aggregate. The control concrete of grade M60 was proportioned following BIS 10262-2009. The crushed waste glass has been used as a partial replacement with varying percentages of 10, 20, 30, and 40% by weight of fine aggregate. Experimental tests were carried on the fresh and hardened state of the concrete. The effect of crushed waste glass on the workability of the concrete has been investigated. Non-destructive tests, acid attack tests, compressive strength, split tensile strength, and X-ray diffraction analysis was carried out for the control concrete and concrete containing crushed waste glass after 7, 28, and 270 days of normal curing. The results show that for the same w/c ratio, the workability of concrete increases with increasing replaced crushed waste glass content. However, the decrease in compressive strength of the concrete after 28 days of normal curing and further after 28 days of acid attacks, up to 30% replacement level of fine aggregate by the crushed waste glass is insignificant.

Key Words
admixture; concrete; crushed waste glass; durability; X-ray diffraction analysis

Address
Department of Civil Engineering, Jamia Millia Islamia, Jamia Nagar, New Delhi, India

Abstract
In this paper, the important novelty and the defining a physical phenomenon of the resent research is the development of nonlocal stress and strain parameters on the porous sandwich beam with functionally graded materials in the top and bottom face sheets. Also, various beam models including Euler-Bernoulli, Reddy and the generalized formulation of two-variable beam theories are obtained in this research. According to a nonlocal strain elasticity theory, the strain at a reference point in the body is dependent not only on the stress state at that point, but also on the stress state at all of the points throughout the body. Thus, the nonlocal stress-strain elasticity theory is defined that can be actual at micro/nano scales. It can be seen that the critical buckling load and transverse deflection of sandwich beam by considering both nonlocal stress-strain parameters is higher than the nonlocal stress parameter. On the other hands, it is noted that by considering the nonlocal stress-strain parameters simultaneously becomes the actual case.

Key Words
a nonlocal stress-strain elasticity theory; bending and buckling analysis; functionally graded facesheets; porous core; sandwich beam

Address
Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran

Abstract
This review article highlights the physical, mechanical, and chemical properties of coconut shells, and the fresh and hardened properties of the coconut shell concrete are summarized and were compared with other types of aggregates. Furthermore, the structural behavior in terms of flexural, shear, and torsion was also highlighted, with other properties including shrinkage, elastic modulus, and permeability of the coconut shell concrete. Based on the reviewed literature, concrete containing coconut shell as coarse aggregate with normal sand as fine showed the 28- day compressive strength between 2 and 36 MPa with the dried density range of 1865 to 2300 kg/m3. Coconut shell concretes showed a 28-day modulus of rupture and splitting tensile strength values in the ranges of 2.59 to 8.45 MPa and 0.8 to 3.70 MPa, respectively, and these values were in the range of 5-20% of the compressive strength. The flexural behavior of CSC was found similar to other types of lightweight concrete. There were no horizontal cracks on beams which indicate no bond failure. Whereas, the diagonal shear failure was prominent in beams with no shear reinforcements while flexural failure mode was seen in beams having shear reinforcement. Under torsion, CSC beams behave like conventional concrete. Finally, future recommendations are also suggested in this study to investigate the innovative lightweight aggregate concrete based on the environmental and financial design factors.

Key Words
chemical composition; coconut shell concrete; flexural and shear behavior; mechanical properties; torsion; permeability

Address
Muhammad Fahad Ejaz: Department of Civil and Environmental Engineering, Saitama University, Saitama, Japan
Muhammad Aslam, Waqas Aziz, M. Jahanzaib Khalil and Aayzaz Ahmed: Department of Civil Engineering, School of Engineering and Technology,Institute of Southern Punjab, Multan, Pakistan
M. Jahanzaib Ali and Muhammad Raheel: Department of Civil Technology, Government College of Technology, Multan, Pakistan

Abstract
In the present work, we proposed an analytical study on buckling behavior of a sandwich plate with polymeric core integrated with piezo-electro-magnetic layers such as BaTiO3 and CoFe2O4 reinforced by graphene platelets (GPLs). The Halpin-Tsai micromechanics model is used to describe the properties of the polymeric core. The governing equations of equilibrium are obtained from first-order shear deformation theory (FSDT) and the Navier's weight fraction of GPLs, and also effect of electric and magnetic field on critical buckling load. The result of this study can be obtained in the aerospace industry and also in the design of sensors and actuators.

Key Words
buckling analysis; FSDT; graphene platelets; Halpin-Tsai model; piezo-electro-magnetic face sheets; polymeric core; sandwich plate

Address
Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran

Abstract
Softening function is the primary input for modeling the fracture of concrete when the cohesive crack approach is used. In this paper, based on the laboratory data on notched beams, an inverse algorithm is proposed that can accurately find the softening curve of the concrete. This algorithm uses non-linear finite element analysis and the damage-plasticity model. It is based on the kinematics of the beam at the late stages of loading. The softening curve, obtained from the corresponding algorithm, has been compared to other softening curves in the literature. It was observed that in determining the behavior of concrete, the usage of the presented curve made accurate results in predicting the peak loads and the load-deflection curves of the beams with different concrete mixtures. In fact, the proposed algorithm leads to softening curves that can be used for modeling the tensile cracking of concrete precisely. Moreover, the advantage of this algorithm is the low number of iterations for converging to an appropriate answer.

Key Words
cohesive crack model; concrete; fracture process zone; inverse analysis; softening curve

Address
Department of Civil Engineering, Shahid Rajaee Teacher Training University, Lavizan, Tehran, Iran

Abstract
Carbon Fiber Reinforced Polymer (CFRP) composite provides outstanding mechanical capabilities and is therefore popular in the automotive and aerospace industries. Drilling is a common final production technique for composite laminates however, drilling high-strength composite laminates is extremely complex and challenging. The delamination of composites during the drilling at the entry and exit of the hole has a severe impact on the results of the holes surface and the material properties. The major goal of this research is to investigate contemporary industry solutions for drilling CFRP composites: enhanced edge geometries of cutting tools. This study examined the occurrence of delamination at the entry and exit of the hole during the drilling. For each of the 80*). The feed rate was determined to be the most efficient factor in preventing hole entry and exit delamination using analysis of variance (ANOVA). Regression analysis was used to create first-degree mathematical models for each cutting tool

Key Words
ANOVA; delamination; drilling; regression

Address
Feroz Shaik and Ramakrishna Malkapuram: Department of Mechanical Engineering, Vignan's foundation for Science, Technology and Research, Guntur, Andhra Pradesh-522213, India
K. Chandra Shekar: Department of Mechanical Engineering, Vignan's Institute of Technology and Science, Deshmukhi (V), Yadadri Bhuvanagiri Dist-508284, Telangana, India
P. Dhaval Varma: Department of Mechanical, Materials and Manufacturing, University of Nottingham, United Kingdom


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