Wyniki wyszukiwania - BazTech

1

Modeling Lamellar Cracks

Jaroniek M., Niezgodziński T.

Mechanics and Mechanical Engineering

|

2013

|

Vol. 17, nr 3

225--234

EN

In this work, studies of models simulating lamellar cracks were conducted. These cracks are formed in rolled sheets with non-metallic inclusions. Studies of lamellar cracks began in the 1960s, but there is still no satisfactory theory explaining their formation. In this work, the application of modeling of samples with non-metallic inclusions for the study of lamellar cracking has been presented. Studies were conducted using two research methods: the photoelastic method and the finite element method. The possibility of crack formation was analyzed in models generated from images obtained from metallographic specimens.

2

Application of Photoelasticy for Study of Lamellar Cracks

Jaroniek M., Niezgodziński T.

Mechanics and Mechanical Engineering

|

2013

|

Vol. 17, nr 3

235--249

EN

In rolled sheets, non–metallic inclusions are distributed along the thickness of the sheet as narrow lines running parallel to the rolling direction. Such inclusions are the nuclei of lamellar cracks. This work presents the application of the photoelastic method for study of lamellar cracking. Photoelastic models of samples with long artificial fissures set in the area of the sheet axis were studied along with other encountered inclusion distributions. The studied samples were placed in a polariscope and subjected to uniform tension; isochromatic images were obtained. Changes in the stress state in the area of the inclusion were observed as the load increased. Stress concentration leads to the formation of lamellar cracks – the joining of voids in the direction parallel to the exterior surface of the sheet (so–called ”terraces” are formed) and at angles (so–called ”jogs” are formed). The results of photoelastic tests were compared with the results of numerical calculations using the finite element method.

3

Wpływ zróżnicowania temperatury formy wtryskowej na odkształcenia wyprasek z PMMA i MABS

Mazik K., Jaruga T., Modławski M.

Przetwórstwo Tworzyw

|

2012

|

[R.] 18, nr 5

478-484

PL

W niniejszym artykule został przedstawiony wpływ różnicy temperatury formy wtryskowej pomiędzy jej ruchomą i nieruchomą częścią na odkształcenia, a w szczególności na wartość strzałki ugięcia wypraski. W przeprowadzonych badaniach użyto dwóch gatunków transparentnych tworzyw polimerowych: poli(metakrylanu metylu) - PMMA oraz tworzywa (metakrylan metylu)-akrylonitryl-butadien-styren (MABS). Przedstawiono wyniki pomiarów odkształcenia wyprasek oraz wyniki badań elastooptycznych i ich analizę. Określono wzór opisujący zależność pomiędzy strzałką ugięcia a zmiennymi warunkami procesu przetwórstwa.

EN

The influence of the injection mould temperature difference between its movable and fixed part on deformation and, in particular, the value of the deflection of the part was presented in this paper. In the studies two grades of transparent polymeric materials: poly(methyl methacrylate) - PMMA and (methyl methacrylate)-acrylonitrile-butadiene-styrene plastic - MABS were used. The results and analysis of photoelastic tests and measurements of moulded parts deflection were presented. A formula describing the relationship between the deflection and the variable parameters of the study was determined.