27562

تاثير حفره و سطح مشترك الياف/رزين برروي استحكام عرضي كامپوزيتهاي پليمري تقويت شده با الياف تك جهته با استفاده از روش ميكرومكانيك محاسبات

كارشناسي ارشد

مهندسي مكانيك-طراحي كاربردي

1398

1401/07/04

دكتر فتح اله طاهري بهروز

مهندسي مكانيك

در اﯾﻦ ﭘﺎﯾﺎن ﻧﺎﻣﻪ اﺛﺮ ﺣﻔﺮه ﻫﺎ ﺑﺮ ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﻋﺮﺿﯽ ﮐﺎﻣﭙﻮزﯾﺖ ﻫﺎي ﺗﻘﻮﯾﺖ ﺷﺪه ﺑﺎ اﻟﯿﺎف ﺗﮏ ﺟﻬﺘﻪ ﺑﺎ اﺳﺘﻔﺎده از روش ﻫﺎي ﻣﯿﮑﺮوﻣﮑﺎﻧﯿﮏ ﻣﺤﺎﺳﺒﺎﺗﯽ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. رﻓﺘﺎر ﮐﺎﻣﭙﻮزﯾﺖ ﺑﺎ ﺗﺠﺰﯾﻪ و ﺗﺤﻠﯿﻞ اﻟﻤﺎن ﻣﺤﺪود ﯾﮏ ﻫﺎ ﺑﻪ ﺻﺮاﺣﺖ ﮔﻨﺠﺎﻧﺪه ﺷﺪه ﺳﺎزي ﺷﺪه اﺳﺖ ﮐﻪ در آن ﺗﻮزﯾﻊ ﺗﺼﺎدﻓﯽ اﻟﯿﺎف و ﺣﻔﺮه ﻋﻨﺼﺮ ﺣﺠﻤﯽ ﻧﻤﺎﯾﻨﺪه ﺷﺒﯿﻪ ﺳﺎزي ﺷﺮاﯾﻂ ﻣﺮزي ﭘﺮﯾﻮدﯾﮏ ﺑﻪ دﻟﯿﻞ ﻃﻮﻻﻧﯽ ﺑﻮدن ﻓﺮآﯾﻨﺪه ¬ اﺳﺖ. در ﻃﺮاﺣﯽ اﻟﻤﺎن دو ﺑﻌﺪي و ﻫﻤﭽﻨﯿﻦ ﭘﯿﺎده ﺑﯿﻦ اﻟﯿﺎﻓﯽ و ﺣﻔﺮه رزﯾﻨﯽ ¬ ﺳﺎزي از ﮐﺪﻫﺎي ﭘﺎﯾﺘﻮن در ﻗﺎﻟﺐ اﺳﮑﺮﯾﭙﺖ ﻓﺎﯾﻞ اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. دو ﻧﻮع ﺣﻔﺮه ¬ ﺷﺒﯿﻪ ﯾﻌﻨﯽ ﺷﮑﺴﺖ رزﯾﻦ و ﺟﺪاﯾﺶ ﺳﻄﺢ ﻣﺸﺘﺮك ، ﻫﺎي آﺳﯿﺐ واﻗﻌﯽ در ﮐﺎﻣﭙﻮزﯾﺖ در رﯾﺰﺳﺎﺧﺘﺎر ﮔﻨﺠﺎﻧﺪه ﺷﺪﻧﺪ و ﻣﮑﺎﻧﯿﺰم ﻫﺎي رزﯾﻨﯽ ﺑﺎ اﻧﺪازه ﻫﺎي ﻣﺨﺘﻠﻒ ﺑﻪ ﺻﻮرت ﺗﺼﺎدﻓﯽ داﺧﻞ ¬ در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﺷﺪه اﺳﺖ. ﻫﻤﭽﻨﯿﻦ ﺣﻔﺮه ، اﻟﯿﺎف/رزﯾﻦ درﺻﺪ( ﻣﻨﺠﺮ ﺑﻪ ﮐﺎﻫﺶ زﯾﺎدي در اﺳﺘﺤﮑﺎم ﻋﺮﺿﯽ 5-1 رزﯾﻦ ﻗﺮار داده ﺷﺪﻧﺪ. ﻣﺸﺨﺺ ﺷﺪ ﮐﻪ ﺣﻔﺮه-ﻫﺎ )در ﻣﺤﺪوده ﻫﺎي ﺑﯿﻦ اﻟﯿﺎﻓﯽ اﺳﺖ. ﺗﺄﺛﯿﺮ ﻫﺮ دو ﻧﻮع ¬ ﺷﻮﻧﺪ و درﺻﺪ زﯾﺎدي از اﯾﻦ اﻓﺖ اﺳﺘﺤﮑﺎم ﺑﻪ واﺳﻄﻪ ﺣﻔﺮه ¬ ﮐﺸﺸﯽ ﻣﯽ ﺣﻔﺮه ﺑﻪ ﺻﻮرت ﻫﻤﺰﻣﺎن و ﺑﻪ ﺻﻮرت ﺟﺪاﮔﺎﻧﻪ در ﺷﺮوع و اﻧﺘﺸﺎر آﺳﯿﺐ در ﺳﺮاﺳﺮ رﯾﺰﺳﺎﺧﺘﺎر، ﺗﺤﺖ ﮐﺸﺶ ﻋﺮﺿﯽ و دﻫﺪ ﮐﻪ اﺳﺘﺤﮑﺎم ﮐﺎﻣﭙﻮزﯾﺖ ﻫﺎ ﺑﻪ ﻃﻮر ﻗﺎﺑﻞ ﺗﻮﺟﻬﯽ ﺑﺎ ¬ ﺑﺮش ﺧﺎرج ﺻﻔﺤﻪ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽ وﺟﻮد ﺣﻔﺮه ﻫﺎ ﮐﺎﻫﺶ ﻣﯽ ﯾﺎﺑﺪ.

1401/09/29

effect of void and fiber/matrix interface on transverse strength of polymer composites reinforced with unidirectional fibers using computational micromechanics metho

9/26/2023 12:00:00 AM

In this study, the effect of voids on the transverse mechanical properties of composites reinforced with unidirectional fibers has been studied using computational micromechanical methods. The behavior of the composite is simulated by finite element analysis of a representative volume element in which the random distribution of fibers and voids is explicitly included. In the design of the two-dimensional element, as well as the implementation of the periodic boundary conditions, due to the long simulation process, Python codes have been used in the form of a script file. Two types of inter-fiber voids and matrix voids were included in the microstructure, and real damage mechanisms in the composite, such as resin fracture and separation of the fiber/resin interface, were considered. Also, resin holes with different sizes were placed randomly inside the resin. It was found that voids (in the range of 1-5%) lead to a great decrease in transverse tensile strength, and a large percentage of this strength loss is due to inter-fiber voids. The effect of both types of void was studied simultaneously and separately in the initiation and propagation of damage throughout the microstructure under transverse tension and out-of-plane shear. The results show that the strength of composites decreases significantly with the presence of voids.

حفره , بين اليافي , ميكرومكانيك محاسباتي , مكانيزمهاي آسيب , افت استحكام

Void , interfiber , computational micromechanics , damage mechanisms , strength loss

Mehrzad Barari tajani

Fathola Taheri behrooz