Interlaboratory proficiency testing of tensile and flexural testing for cellulose based transformed board material

Optimum safety and reliability can be achieved by coordinating an interlaboratory proficiency testing among different laboratories. Testing laboratories need to verify their test procedures and testing capability for reliable results. In this study, equivalent samples are prepared by cellulose based transformed board material used in transformers as electrical isolation material. Randomly selected test samples having specified dimensions are sent to the participant laboratories. Then they are tested and results are analyzed according to previously defined parameters. Each laboratory applied tensile and flexural tests on the samples according to procedures given in IEC 60641-2, 2004 and IEC 60763-2, 2007 standards respectively. Test results are evaluated according to same procedures explained in related standards by the participant laboratories. TUBITAK UME Material Testing Laboratory being the pilot laboratory collected to the all evaluated results including associated measurement uncertainties. Then the collected results evaluated according to ISO 17043, 2010 are reported by each laboratory as a part of the proficiency test report. Z-scores of the participant laboratories are presented

Calculation of measurement uncertainty for cellulose based transformed board material in tensile testing

Today’s global economy obliges manufacturers to produce their products in high quality with cheaper cost. Thus, manufacturers must develop their products applying tests to get better performance and higher quality before distributing them to the competitive market. In order to produce long working life of transformer reactors without losing their performance, different tests including axial and flexural testing are applied on the cellulose based laminated board material used in production. During development of laminated board material, test results should be known very well and the measurement uncertainty of tensile tests should be calculated taking into account all parameters. In this study, effective parameters on the quality of tensile testing causing an increase on the measurement uncertainty are investigated. Tensile strength and elongation test of laminated board material were carried out according to IEC 60641-2 and the uncertainty contributions based on experimental results were calculated. The results and impact of the uncertainty parameters are presented in detail

Forças verticais e de atrito em silos cilíndricos com fundo plano

A predição exata das forças que atuam no corpo de um silo é um dos principais problemas, no que tange ao quesito dimensionamento dessas estruturas. Com o objetivo de mensurar as forças atuantes no fundo e nas paredes dos silos durante o processo de descarregamento foram instrumentados, por meio de células de carga e células de pressão, a parede e o fundo de um silo piloto vertical cilíndrico com fundo plano. As leituras das células foram realizadas por sistema automático de aquisição de dados durante o carregamento e o descarregamento de areia seca. O silo foi carregado concentricamente e descarregado concêntrica e excentricamente, a partir de duas excentricidades. O experimento ocorreu no período de janeiro a abril de 2008, no Laboratório de Construções Rurais e Ambiência da Universidade Federal de Campina Grande, PB. Os valores experimentais foram confrontados com os prescritos pelas normas Eurocode 1, ISO 11697, AS 3774 e DIN 1055. Conclui-se, então, que os valores teóricos de força vertical propostos pelas normas foram superestimados em relação aos obtidos experimentalmente para a maioria das formas de descarregamento. Para a força de atrito nas paredes as normas produziram resultados compatíveis com os obtidos experimentalmente

Final report on force key comparison CCM.F-K2.a and CCM.F-K2.b (50 kN and 100 kN)

The CCM Force Working Group met in October 1998 in Sydney and made decisions about CIPM Key Comparisons for the unit of force. These were to cover four force ranges, with four different pilot laboratories: i) 5 kN – 10 kN Pilot: MIKES-Raute, Finland ii) 50 kN – 100 kN Pilot: NPL, United Kingdom iii) 500 kN – 1 MN Pilot: PTB, Germany iv) 2 MN – 4 MN Pilot: NIST, USA This report gives the results for Key Comparison ii), piloted by NPL and officially designated CCM.F-K2.a (Scheme A) and CCM.F-K2.b (Scheme B) by CIPM (see Section 4 for details of Scheme A and Scheme B)