Fatigue and fracture in polyacetal resins

被引：15

作者：

Lazzeri, A ^{[1
]}

Marchetti, A ^{[1
]}

Levita, G ^{[1
]}

机构：

[1] POLITECN MILAN,DIPARTIMENTO CHIM IND & INGN CHIM,I-20123 MILAN,ITALY

来源：

FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES | 1997年 / 20卷 / 08期

关键词：

fatigue crack propagation; fracture toughness; molar mass degradation; polyacetal resins; polyoxymethylene (POM); RUBBER-TOUGHENED POLYMERS; POLYOXYMETHYLENE;

D O I：

10.1111/j.1460-2695.1997.tb00324.x

中图分类号：

TH [机械、仪表工业];

学科分类号：

0802 ;

摘要：

The fatigue behaviour of polyoxymethylene (POM) of different molar mass (6.1 x 10(4)-1.5 x 10(5)) was studied at stress levels from 35 to 50 MPa (about 55 and 75% of the yield strength, respectively). It was found that cyclic loadings promoted bond breaking of the polymeric chains which considerably reduced the molar mass both in the crack tip region of cracked specimens and in the bulk in the case of uncracked samples. This process probably included the formation of reactive radicals which subsequently favoured the formation of microvoids that weakened the material. The static fracture toughness of fatigued samples decreased on increasing the stress level, the process accelerating as the cyclic loads approached the yield strength. As a result of material modifications during the tests the low molar mass resins did not exhibit stable crack propagation.

引用

页码：1207 / 1216

页数：10