• Journal of Advanced Marine Engineering and Technology
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• 제31권6호
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• pp.753-760
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• 2007

For protection of the cylinder wall of the ball mill for grinding raw ore. the inner side of the cylinder is covered with rubber liner. The rubber is easily worn down because the rubber relatively soft compared with raw ore. So the rubber liner in the ball mill cylinder must be replaced almost every year and the cost for replacing rubber liner formidable. In this paper, for reducing or excluding the cost of replacing rubber liner the basalt liner is designed. The basalt materials are generally harder than raw ore and the basalt liner in the ball mill does not wear down and so it can be used almost permanently. The concave surfaces are made on the liner of the ball mill and the liner in the cylinder wall plays also the role of raising the steel balls mixed in the raw ore. The section profiles of the concave surface have an important effect on the performance of the ball mill. The deep concave grooves raise the steel balls to high levels and give the large potential energy to the steel balls impacting to the raw ore. But if the concave grooves are too deep. the steel balls raised too high by the concave grooves fly along the parabolic path and reach to the other side of cylinder wall and so the steel balls do not play the roles of grinding the raw ore. The forces acting to a steel ball in a concave groove of the cylinder liner are also analyzed in this paper. The formulas calculating the height and the impact point of the steel ball are introduced and presented. Based to these formulas, the optimum section profiles of the basalt liner are presented.

• 한국정밀공학회지
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• 제32권3호
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• pp.269-277
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• 2015

Compressed natural gas (CNG) composite vessels for vehicles have been generally made of 34CrMo4 for a inner liner part and E-glass/epoxy for a composite layer part. But, there is a problem of material loss of CNG composite vessels used in vehicles due to the design of excessive thickness of the liner. And, light weight of the CNG composite vessel is required for improving fuel efficiency. In this study, optimal design for CNG composite pressure vessel was performed by using basalt fiber, which is the environment-friendly material having a good mechanical strength. The optimal thickness of each part (inner liner and composite layer) was determined by theoretical analysis and FEA for satisfying structural safety and lightweight of the vessel. Also, for improving fatigue life, optimal autofrettage pressure was derived from FEA results.

• Journal of Advanced Marine Engineering and Technology
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• 제31권4호
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• pp.401-409
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• 2007

Because of the various excellent characteristics of cast basalt materials. such as, anti-corrosion, anti-wearing, good hardness. high chemical stability, of which steel may not possess, the steel-basalt composite pipes are used in severe environments for compensating the defects of steel. However. without sufficient mechanical investigation prior to application. the basalt liners in steel-basalt composite pipes may be cracked and broken or the basalt liners are omitted from steel pipes in applications. In these cases, the merits of basalt materials may disappear and the basalt liners may not play their good roles as expected. Therefore, it is required that mechanical behavior of steel-basalt composite pipes and surrounding environments be fully examined before installation. The limit of bending moment with which steel-basalt composite pipe may safely endure is calculated and the limit curvature of the composite pipe in the safe range is presented in this paper. The temperature distributions and the thermal stresses are also computed and the limit difference of temperatures between inner and outer side of composite pipe is given together.

• 한국지반신소재학회논문집
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• 제14권2호
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• pp.89-94
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• 2015

본 연구에서는 제주도 내에서 발생되는 현무암 석분슬러지를 차수용 재료로 재활용하기 위하여 최적의 석분슬러지 혼합비를 가진 혼합토를 선정하고자 한다. 토질시험결과에 따르면 현무암 석분슬러지의 입경은 대부분 0.1mm 이하이고, 토질의 분류기준인 통일분류법(USCS)을 적용하면 ML 및 CL에 해당한다. 그리고 현장토의 입경은 0.1-10mm 사이에 존재하고, 통일분류법(USCS)을 적용하여 분류하면 SW에 해당한다. 최적의 석분슬러지 혼합비를 가진 혼합토를 선정하기 위하여 다양한 석분슬러지 혼합비를 가진 혼합토를 대상으로 최적 다짐조건 및 현장조건을 고려하여 투수시험을 수행하였다. 투수시험결과 석분슬러지 혼합비가 증가함에 따라 혼합토의 투수계수는 감소하는 경향을 보이며, 석분슬러지의 혼합비가 60%인 경우 가장 낮은 투수계수를 갖는다. 따라서 현무암 석분슬러지를 차수용 재료로 재활용하기 위한 석분슬러지 혼합토의 최적 혼합비는 60%임을 알 수 있다.