Papers by Keyword: Crushing

Abstract: Concrete structures may become obsolete and be unfit for use to the extent that they need special attendance of repair or strengthening so as to revive them. The weakness in the buildings may be caused by natural disasters like earthquake, floods, changes of use of the buildings in which higher loads more than the design loads, e.g. vertical extension loads, are applied. When the structures are defective they need to be strengthened in order to restore their original structural integrity. Sometimes, the defect or deterioration needs to be scientifically analysed first in order to know the root cause of the problem and apply the right corrective measures. A case study on an eleven stories damaged building in is presented, starting with an investigation on causes of sudden crushing of one column and a strengthening method which embraced a number of techniques such as Land Surveying and non-destructive tests in assessing the building structural integrity. The crushed column and other columns is the ground floor were all strengthened using jacketing method and provision of additional columns at the crushed column. Keywords: Columns, crushing, non-destructive tests, concrete quality, deflection, plumb, jacketing, strengthening

Abstract: This research provides the analysis of the mill scale and plastic waste properties, as well as ways of their complex recycling. Preliminary experiments on the formation of briquettes were made. The results of preliminary experiments on mill scale grinding in a cone inertial crusher and the formation of briquettes together with plastic are presented. This research has revealed the possibility of creating a briquette charge material for further processing in steelmaking processes. The addition of a plasticizer is necessary to improve the formability of the samples during pressing.

Abstract: The effect of aluminum foams with different cell structure on the quasi-static compression behavior and energy absorption of aluminum tubular structures was investigated. For comparison, empty tubes and aluminum foams with different cell structure were also tested, respectively. The results indicated that the value of crushing peak load of aluminum foam-filled tubes increases from 57.88% (1.94mm cell size) to 89.33% (1.22mm cell size) respectively compared with 2.83mm cell size. Splitting deformation of foam filling was found to effect in increasing the extra contact between the foam filling and the tube during progressive crushing, which increases the lateral compressive forces on the tubes. The energy absorption of aluminum foams filled aluminum tubes was also improved significantly due to the change of cell structure.

Abstract: The aim of this study is to find the best platen with blades as a new energy dissipating mechanism that causes considerably damage to CFRP/aluminium tubes. Specially designed and manufactured platens with five different cutting blade profiles were used to simultaneously cut and crush square CFRP tubes and aluminium sheet-wrapped CFRP tubes. The platens with blades were evaluated in terms of the deformation mode, mean crushing force, energy absorption and specific energy absorption of tubes. Experimental results showed that tubes cut and crushed by the platen with 45^o inclined blades had the best crushing performance and exhibited a more stable deformation mode compared with those for tubes cut and crushed by other platens with different blade profiles. The platens with blades acted as trigger mechanisms that minimise the initial peak crushing force and maximise the energy absorption of tubes compared with tubes crushed by flat loading platens.

Abstract: The effectiveness of date palm fibers as a second order filler was assessed in octagonal/hexagonal hybrid energy absorption devices.. The cells inside the device were made from carbon fiber-reinforced plastics CFRP whereas; the outer skin was of Aramid/epoxy. The energy absorption devices were filled by date palm fibers and then the liquid foam was applied. The idea is to use the fibers to absorb the energy in various damage mechanisms and use the foam as a binder. The comparison showed higher peak load and average crushing load (for some cases) for the specimens filled with date palm and foam together. On the other hand, the specimens filled with foam only showed higher stroke efficiency and lower weight which led to a higher specific energy absorption.

Abstract: In this study, hollow square carbon fibre reinforced plastic (CFRP) tubes and aluminium sheet wrapped CFRP tubes have been axially crushed at a quasi-static loading velocity of 0.05 mm/s. A specially designed and manufactured platen with four cutting blades was used to cut and crush these two tubular structures. The four cutting blades had height of 5 mm and width of 3 mm with round tip to reduce the initial peak force and achieve a stable crushing deformation mode. Notches at one end of each tube were utilized to control the location of initial failure. The crashworthiness characteristics of hollow CFRP tubes and aluminium sheet wrapped CFRP tubes with notches that crushed by the platen with cutting blades were compared with those of tubes that crushed by a flat platen. Experimental results showed that using the platen with blades to crush the specimens with notches exhibited more stable deformation mode than the specimens without notches. Mean crushing force, energy absorption and specific energy absorption (SEA) increased when CFRP was wrapped with aluminium sheet and crushed by the platen with blades. The increase of average value of mean crushing force, energy absorption and specific energy absorption of aluminium sheet wrapped CFRP tube and crushed by the platen with blades are 16.5%, 17.3% and 5% respectively more than those for hollow tubes that crushed by a flat platen.

Abstract: The paper presents simulation of the stress-strain state of various designs of disk tool attachment points on triangular prisms of radial bits of the roadheaders working body when cutting of coal and rock face.

Abstract: Hainan Island has a good reputation for "Coconut Island". The production of coconut is more than 80 percent in China. However, the development of coconut industry in Hainan lags behind when compared to other industries, because the comprehensive use ratio of coconut is still less. One reason of barring the coconut industry development owes to lacking of a good method to smash the coconut shell. Contraposing the current single method of smashed coconut shell, the low productivity and other problems, I design an achievable and automated coconut shell crusher based on the PLC control program to resolve the problem of artificial broken coconut shell, to save labor forces, to shorten labor time, to improve the production efficiency, to improve the utilization rate of coconut, to expand the economic benefits, and to promote the development of coconut industry.

Abstract: The objective of this study was to determine the energy absorption of basalt filament wound rectangular tubes under crushing test. Basalt fibre gained a lot of potential in various application due to low cost of this material together with its capability to breaking the domination of e-glass as a reinforcement material. Coupon tensile and axial compression (crushing) test were performed to investigate the strength and energy absorption performance of basalt filament wound rectangular tubes. Both test have been conducted using [±70⁰]₃ winding angle of sample configuration and comparison have been made in coupon test in which the basalt sample shows 8.7% higher than e-glass while produced opposite results in modulus of elasticity. Crushing test was performed in 25mm displacement with different loading rate which are 5, 10 and 15mm/min. The results obtained from three different conditions were compared showing a higher energy absorbed in the lower loading rate. The comparable crashworthiness of basalt suggest possible applications such as automotive industry which is requires a good energy absorb materials in some particular components.

Abstract: Magnesium MgO exists in nature in large quantities as magnesite (MgCO₃) and dolomite (CaMg (CO₃)₂), and in lesser amounts than oxide in the form of mineral called periclase. Magnesite refractory material containing MgO may be obtained from the high purity magnesite ore simple purification and subsequent calcination at a temperature of 500-700 °C.