本文選題：半圓形單邊切口梁　切入點(diǎn)：雙K斷裂參數(shù)　出處：《浙江大學(xué)》2015年碩士論文

【摘要】：混凝土結(jié)構(gòu)受荷破壞前,裂縫擴(kuò)展要經(jīng)歷三個(gè)階段：裂縫起裂；裂縫穩(wěn)定擴(kuò)展和失穩(wěn)破壞。雙K斷裂模型采用起裂韌度Klcm和失穩(wěn)韌度K1cun,很好地描述了混凝土材料中裂縫擴(kuò)展的這三個(gè)重要階段。起裂韌度定義為起裂荷載時(shí)刻對(duì)應(yīng)的初始裂縫尖端應(yīng)力強(qiáng)度因子值,失穩(wěn)韌度定義為最大荷載時(shí)刻臨界裂縫尖端的應(yīng)力強(qiáng)度因子值。本文采用半圓形單邊切口梁測(cè)定了混凝土的雙K斷裂參數(shù)。分別采用三種不同直徑(200,400和500 mm)的半圓形單邊切口梁和四種不同強(qiáng)度(C2,C3,C4和C5)的混凝土進(jìn)行斷裂試驗(yàn),研究試件尺寸及混凝土強(qiáng)度對(duì)雙K斷裂參數(shù)的影響。試驗(yàn)結(jié)果表明,采用半圓形單邊切口梁測(cè)定的起裂韌度值和失穩(wěn)韌度值均具有尺寸效應(yīng)；此外,混凝土雙K斷裂參數(shù)還受混凝土強(qiáng)度的影響。隨著試件尺寸增大,臨界等效裂縫長度ac,臨界裂縫口張開位移CMODc和失穩(wěn)韌度均增大；而起裂韌度隨試件尺寸的增大而減小。
[Abstract]:Before the concrete structure is damaged by load, the crack propagation has to go through three stages: crack initiation; The dual K fracture model uses the initial fracture toughness (Klcm) and the instability toughness (K _ 1 cununi) to describe the three important stages of crack propagation in concrete. The initial fracture toughness is defined as the initial crack loading moment. Stress intensity factor at the tip of the initial crack, The instability toughness is defined as the stress intensity factor value at the critical crack tip at the maximum load moment. In this paper, the double K fracture parameters of concrete are measured by using a semicircular one-sided notch beam with three different diameters of 200400 and 500mm, respectively. Fracture tests were carried out on circular unilateral notched beams and four kinds of concrete with different strength (C _ 2C _ 3C _ 3C _ 4 and C _ 5). The effects of specimen size and concrete strength on double K fracture parameters are studied. The experimental results show that both the initial fracture toughness and the instability toughness measured by the semicircular one-sided notch beam have a size effect. With the increase of specimen size, critical equivalent crack length ac. critical crack opening displacement CMODc and instability toughness increase, while initial fracture toughness decreases with the increase of specimen size.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU528

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相關(guān)期刊論文 前2條

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本文編號(hào)：1685557