تأثیر رطوبت نسبی و درجه حرارت بر مؤلفه‏های خزشی تخته فیبر با دانسیتۀ متوسط (MDF)

نوع مقاله: مقاله پژوهشی

نویسندگان

1 کارشناس ارشد علوم و صنایع چوب و کاغذ، دانشکدۀ منابع طبیعی، دانشگاه تربیت مدرس، نور، ایران

2 دانشیار گروه علوم و صنایع چوب و کاغذ، دانشکدۀ منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس، نور، ایران

چکیده

در این پژوهش، رفتار خزشی تخته فیبر با دانسیتۀ متوسط (MDF) تحت شرایط رطوبت نسبی و دماهای مختلف بررسی شد. بدین‌سبب، آزمون خزش خمشی در دو سطح بارگذاری 15 و 30 درصد بار شکست خمشی نمونه‏ها (بار شکست به‏دست‏آمده از آزمون خمش استاتیک) انجام شد. نمونه‏ها به مدت 72 ساعت در رطوبت‏های نسبی (RH) 45، 65، و 85 درصد و دماهای 15، 23، و 30 درجۀ سانتی‏گراد تحت بارگذاری قرار گرفتند. بررسی نتایج نشان داد که با افزایش دما و رطوبت نسبی میزان خزش نسبی و خیز نهایی نمونه‏ها افزایش یافت، در حالی ‏که مدول خزشی کاهش پیدا کرد که در رطوبت‏ نسبی و دمای بالاتر و همچنین سطح بارگذاری بالاتر، این تغییرات بیشتر است. خزش نسبی به رطوبت نسبی در مقایسه با دما حساسیت بیشتری دارد. برعکس، دما در مقایسه با رطوبت نسبی بر مدول خزشی بیشتر تأثیر دارد که در سطح بارگذاری بالاتر این تغییرات بیشتر است.

کلیدواژه‌ها


عنوان مقاله [English]

Effects of Relative Humidity and Temperature on Creep Parameters of Medium Density Fiberboard (MDF)

نویسندگان [English]

  • Mostafa Ebrahimi 1
  • Saeed Kazemi 2
  • Rabi Behrooz 2
1 MSc. Graduate, Department of Wood and Paper Science and Technology, Faculty of Natural Resources Tarbiat Modares University, Noor, Iran
2 Associated Professor, Department of Wood and Paper Science and Technology, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran
چکیده [English]

In this research, creep behavior of medium density fiber board (MDF) under different conditions (different relative humidity and different temperature) was investigated. For this purpose, flexural creep tests at 15% and 30% of ultimate bending load were performed by using flexural creep equipment. The samples underwent under load at relative humidity of 45, 65 and 85% and temperatures of 15, 23 and 30°C for 72 hours. The results showed that relative creep and total creep of the samples increase with increasing temperature and relative humidity, while the creep modulus decreases with increasing temperature and relative humidity. The greater changes were obtained at higher relative humidity and temperature an also at higher load level. The results also showed that the relative creep is more sensitive to relative humidity compared to temperature. Conversely creep modulus is more sensitive to temperature compared to relative humidity that greater changes have been observed in higher load level.

کلیدواژه‌ها [English]

  • Creep
  • loading levels
  • medium density fiber board (MDF)
  • relative humidity
  • temperature
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