There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Adhesion of polymers

Intermediate crack-induced debonding in RC beams and slabs

FRP-strengthened RC beams. I: review of debonding strength models

https://www.quakewrap.com/frp%20papers/Progress-On-Understanding-Debonding-Problems-In-Reinforced-Concrete-And-Steel-Members-Strengthened-Using-FRP-Composites.pdf

Progress on understanding debonding problems in reinforced concrete and steel members strengthened using FRP composites

The structural behavior of reinforced concrete beams strengthened with adhesively bonded fiber-reinforced plastics (FRP) is presented. The experimental work included flexural testing of 2.3-m-long concrete beams with bonded external reinforcements. The test variables included the amount of conventional (internal) reinforcement and also the type and amount of external reinforcement. For comparison, some of the beams were strengthened with bonded steel plates. Theoretical analyses included 2D nonlinear finite-element modeling incorporating a “damage” material model for concrete. In general there were reasonably good correlations between the experimental results and nonlinear finite-element models. It is suggested that the detachment of bonded external plates from the concrete, at ultimate loads, is governed by a limiting principal stress value at the concrete/external plate interface.

Concrete beams strengthened with externally bonded frp plates

Microwave irradiation of polypropylene surface: a study on wettability and adhesion

Penetration and perforation behavior of glass fiber reinforced plastic (GFRP) plates containing 20% sand filler have been investigated via high velocity impact tests using sharp tipped (30°) projectile and quasi-static perforation tests. Two size sand filler (75 and 600 μm) were used in 4-, 8-, and 14-layered laminated composite plates to study sensitivity of filler size toward loading system. Composite plates were examined for perforation load rate at 5 mm/min and high-velocity impact loading up to 220 m/s. Results indicated higher energy absorption for GFRP plates containing sand filler for both high-velocity impact and quasi-static perforation tests. Higher ballistic limits were recorded for specimens containing sand filler. The study showed clear role played by coarse-sized sand filler as a secondary reinforcement in terms of higher energy absorption as compared with nonfilled and specimens containing fine-sized fillers. The investigation successfully characterized behavior of quasi-static test during penetration and perforation of the sharp-tipped indenter as an aid for impact application studies. Residual frictional load in the specimens containing sand filler constituted considerable portion of load bearing during perforation in quasi-static tests. Delaminations followed by fiber and matrix fracture were major failure mode in high-velocity tests and the main energy absorbing mechanism in thick-walled plates, whereas in quasi-static tests the failures were more of matrix fracture and fiber sliding. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Experimental study of sharp‐tipped projectile perforation of GFRP plates containing sand filler under high velocity impact and quasi‐static loadings

This paper describes the development of a three-dimensional finite element model for the modelling of a 155/65R13 steel-belted tyre under inflation pressure, vertical static (footprint) load, and steady state rolling. The model was created for the ABAQUS/standard code and used to carry out a series of parametric studies. The main purpose was to examine the effect of some structural and operational parameters including type of body and cap plies cords, cord belt angle, and friction coefficient between tyre and road on the mechanical behaviour of the tyre under both static and rolling conditions. It is shown that the belt angle is the most important constructional variable among the selected parameters that affect the tyre behaviour, significantly. The changes of friction coefficient have had great influence on tyre variables at contact zone, e.g., pressure field and relative shear between the tread elements and road as well. The accuracy and reliability of the results obtained in this simulation were also confirmed by comparing two deformational characteristics of the tyre (static deflection and free rolling perimeter) with those of two commercial tyres.

A parametric study on the steady state rolling behaviour of a steel-belted radial tyre

Ballistic performance of glass reinforced plastic (GRP) composite plates containing coarse sized sand filler was investigated as an attempt towards developing a low cost armored system. In all, 10 different types of plates from 4 to 12 layers of E-glass chopped strand mat reinforced polyester resin containing 0, 10, and 20% of 600- to 700-μm sized sand filler were tested. A smooth barrel gas gun was used to conduct high velocity tests in the range of 70–185 m/s. Results indicated higher ballistic performance for GRP plates with sand filler in terms of higher ballistic limits (velocity at which at least 50% of samples were partially or fully penetrated the target plates with zero residual velocity), particularly for plates with highest sand filler loadings. Energy absorption associated with these specimens also showed higher performance. Delamination was identified as dominant failure mode, in particular for thicker specimens with highest sand filler loading. Specific energy absorption per weight per unit area for the composite plates indicated diminishing effectiveness with increase in sand filler loading, thereby limiting its possible application to armored system for stationary objects only. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers

H. Rahimi

Papers

Concrete beams strengthened with externally bonded frp plates

Microwave irradiation of polypropylene surface: a study on wettability and adhesion

Experimental study of sharp‐tipped projectile perforation of GFRP plates containing sand filler under high velocity impact and quasi‐static loadings

A parametric study on the steady state rolling behaviour of a steel-belted radial tyre

High velocity impact behavior of GRP panels containing coarse-sized sand filler