本文選題：混凝土　切入點(diǎn)：應(yīng)變率　出處：《力學(xué)學(xué)報(bào)》2017年04期 　論文類型：期刊論文

【摘要】：混凝土結(jié)構(gòu)在受到動(dòng)載荷作用之前,通常已承受著初始靜載荷的作用.大量關(guān)于混凝土應(yīng)變率效應(yīng)的研究均沒有考慮初始靜載荷對(duì)動(dòng)強(qiáng)度的影響,會(huì)導(dǎo)致過高地估計(jì)混凝土的動(dòng)強(qiáng)度,使混凝土結(jié)構(gòu)設(shè)計(jì)偏于危險(xiǎn).本文通過分析混凝土材料在靜動(dòng)組合載荷下的率效應(yīng)機(jī)理,給出了初始靜載荷的定義.在此基礎(chǔ)上,推導(dǎo)了混凝土材料參數(shù)與初始靜載荷和應(yīng)變率的表達(dá)式,提出了建立靜動(dòng)組合強(qiáng)度準(zhǔn)則的一般方法.通過材料參數(shù)反映初始靜載荷與應(yīng)變率的聯(lián)合影響,給出了由初始有效靜載荷、動(dòng)態(tài)黏聚強(qiáng)度和摩擦強(qiáng)度共同組成的混凝土動(dòng)態(tài)強(qiáng)度,將廣義非線性強(qiáng)度準(zhǔn)則發(fā)展為靜動(dòng)組合多軸強(qiáng)度準(zhǔn)則.建立的強(qiáng)度面在相同初始靜載荷下隨應(yīng)變率的增大向外擴(kuò)張,在相同應(yīng)變率下隨初始靜載荷的增大向里收縮,即混凝土的強(qiáng)度在相同初始靜載荷下隨應(yīng)變率的增大而增大,在相同應(yīng)變率下隨初始靜載荷的增大而減小.此外,當(dāng)初始靜載荷和應(yīng)變率不變時(shí),加載路徑對(duì)混凝土材料的應(yīng)變率效應(yīng)無影響,但會(huì)影響混凝土材料的靜水壓力效應(yīng),即當(dāng)初始靜載荷和應(yīng)變率固定不變時(shí),靜動(dòng)組合強(qiáng)度面的位置和大小即可確定,不同加載路徑下強(qiáng)度的不同是由于靜水壓力效應(yīng)導(dǎo)致的.最后利用多組混凝土材料靜動(dòng)組合強(qiáng)度試驗(yàn)對(duì)建立的靜動(dòng)組合強(qiáng)度準(zhǔn)則進(jìn)行了驗(yàn)證.
[Abstract]:Concrete structures are usually subjected to initial static loads before they are subjected to dynamic loads. Many researches on the strain rate effect of concrete do not consider the effect of initial static loads on dynamic strength. The dynamic strength of concrete will be overestimated, and the design of concrete structure will be more dangerous. In this paper, the definition of initial static load is given by analyzing the mechanism of rate effect of concrete material under static and dynamic combined loads. The expressions of concrete material parameters and initial static load and strain rate are derived, and a general method of establishing static and dynamic combined strength criterion is proposed. The combined effect of initial static load and strain rate is reflected by material parameters. The dynamic strength of concrete composed of initial static load, dynamic cohesion strength and friction strength is given. The generalized nonlinear strength criterion is developed into the multiaxial strength criterion of static and dynamic combination. The strength surface expands outward with the increase of strain rate under the same initial static load, and shrinks inward with the increase of initial static load at the same strain rate. That is, the strength of concrete increases with the increase of strain rate under the same initial static load, and decreases with the increase of initial static load at the same strain rate. The loading path has no effect on the strain rate effect of concrete material, but it will affect the hydrostatic pressure effect of concrete material. That is, when the initial static load and strain rate are fixed, the position and size of the static and dynamic strength surface can be determined. The difference of strength under different loading paths is caused by hydrostatic pressure effect. Finally, the static and dynamic combined strength criterion is verified by the static and dynamic combined strength test of many groups of concrete materials.
【作者單位】： 北京工業(yè)大學(xué)城市與工程安全減災(zāi)教育部重點(diǎn)實(shí)驗(yàn)室;
【基金】：國家自然科學(xué)基金(51522802,51421005) 國家重點(diǎn)研發(fā)計(jì)劃(2016YFC0701104)資助項(xiàng)目
【分類號(hào)】：TU528

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1 李亞軍;;混凝土強(qiáng)度準(zhǔn)則國外研究述評(píng)[J];科技創(chuàng)新導(dǎo)報(bào);2011年11期

2 王立成;宋玉普;;混凝土雙軸受壓動(dòng)態(tài)強(qiáng)度準(zhǔn)則[J];水電能源科學(xué);2012年01期

3 金巨年;三心凹底氣瓶底型設(shè)計(jì)強(qiáng)度準(zhǔn)則探討[J];大連工學(xué)院學(xué)報(bào);1980年02期

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本文編號(hào)：1639970