High molecule physics and the damage theory of rheologic material with lacuna are used in experiments to study the pmma ' s nonlinear viscoelasticity and changing depends on time and temperature when distorting and destroying . we try to seek a common rule to polymer ' s crazing damage , offer a viable damage model and measure to research polymer ' s minute damage 本文運用高分子物理、含缺陷流變性物體的材料破壞等理論,以實驗為基礎,對聚合物變形、破壞以及時間相依和溫度依賴性等非線性力學行為進行研究,試圖尋求聚合物銀紋損傷的一般規律,為研究聚合物的細觀損傷提供了一種可行的損傷模型與方法。
( 2 ) using craze density dcraze ( , ) to illustrate the damage degree of material , considering strain equivalent hypothesis , non - linear visco - elastic constitutive equation of pmma taken into consideration of the operation of craze damage is arrived . the pmma sheet is loaded under different forces to validate the non - linear visco - elastic constitutive equation with damage . the result shows that the theory curves obtained by the nonlinear viscoelasticity constitutive relation agrees with experimental data considerably well ( 2 )用銀紋密度d _ ( craze ) ( , t )來描述材料的損傷度d ,在考慮應變等效性假設的基礎上,得到了pmma材料考慮損傷的非線性粘彈性材料的本構關系,運用此方程對材料在不同載荷水平下進行蠕變實驗,從而對蠕變條件下的應變響應進行模擬和預報。
In this paper , we take high molecule physics and the damage theory of rheologic material with lacuna as the basic , make the experiment as a mostly measure , take the pmma as a research object , to study the pmma ' s nonlinear viscoelasticity of high polymer . the technique showing minute details in minute view measure is used by the author to observe the change of crazing damage density follow the change of stress , time and temperature in term of creep and flab 本文以高分子物理學、含缺陷流變性物體的材料破壞理論為基礎,以實驗為手段,以工程中常用的pmma為研究對象,對pmma銀紋破壞的非線性力學行為進行了研究。作者采用顯微技術,對pmma在蠕變或松弛條件下,不同應力水平和不同基溫下的pmma銀紋損傷進行了實驗研究。
The main purpose of this paper is to study crack growth rate of a class of nonlinear viscoelastic materials under the condition of constant load and small - strain . in this paper : the new test program is raised by referencing the existing test programs and by our trial and error ; in the new test program , facilities involved in the nonlinear viscoelastic crack tests are relatively few , the test process is relatively simple and the data obtained from the experiments are credible . on this basic , the calculation of j integral of nonlinear viscoelastic double cantilever beams specimens and the parameter of fracture work of corresponding nonlinear viscoelasticity are derived 具體成果包括: 1 、證實了雙懸臂梁試件用于非線性粘彈性裂紋擴展實驗研究的優點:雙懸臂梁試件在實驗中能觀測到的擴展過程持續時間比較長,在計算j積分時,計算方法簡單; 2 、得到了改性聚丙烯材料用于非線性粘彈性裂紋擴展實驗的兩種有效的試件構形和相應的試件尺寸;采用不斷改善夾具的方法使得加載穩定; 3 、經過連續四個多月的時間得到了一組有用的實驗數據; 4 、得到了裂紋長度與時間的關系、裂紋擴展速度與時間的關系、裂紋擴展速度與裂紋長度的關系。