Stress State Dependence of Impact Strengths for Engineering Plastics

工程塑料冲击强度的应力状态依赖性

• 批准号: 07555352
• 负责人: TAKAHASHI Kiyoshi
• 金额: $ 0.64万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555352/
• 关键词: Engineering plastics; Polyamide; Stress state; impact; Charpy test; Notch embrittlement

Charpy impact (Mode I) and puncture impact (Mode+I+II+III) tests were adopted to study stress state dependence of impact strengths for engineering plastics. For specimen materials, HIPS,PPE,PBT,PBT/PPE (blend), PA6, PA6/EPR,PA6/PPE/SBS,PA6/PPE/SBS/EPR were employed. Instrumented impact apparatus was used to evaluate impact load, displacement and energy in fracture of the specimens.Impact energy values in both tests, E_<3pb> (Charpy) and E_<pun> (puncture), were defined as follows : E_<3pb>=E/(B・a_l), E_<pun>=E/B, where E is total energy measured by the apparatus, B specimen thickness and a_l length of ligament region.It has been found from the result that the engineering plastics above mentioned can be classified into three categories : (I) PBT and PA6, (II) PBT/PPE,PPE/SBS and PA6/PPE/SBS,(III) PA6/EPR and PE6/PPE/SBS/EPR depending on the stress state dependency. Plastics of class I are quite weak under one dimensional stress concentration, and those of III are tough under both one and mixed three mode stress states. Plastics of class II exhibit toughness in betwen.It is concluded from the study that the method proposed here is available for studying the stress state dependency on impact strength of engineering plastics.A fundamental study was also performed on instrumented impact testing. Oscillation signals from a strain gauge of a dart impacting PC Charpy specimens were experimentally analyzed. A method to place a thin rubber sheet on an impact surface of a specimen is proposed to minimize dynamic effects contained in the dart sugnals.

采用夏比冲击（I型）和穿刺冲击（+I+II+III型）试验研究了工程塑料冲击强度的应力状态依赖性。试样材料采用HIPS、PPE、PBT、PBT/PPE（共混）、PA6、PA6/EPR、PA6/PPE/SBS、PA6/PPE/SBS/EPR。采用冲击仪对试件的冲击载荷、位移和断裂能进行了评估。两个试验的冲击能值E_<3pb> (Charpy)和E_<pun>（穿刺）定义如下：E_<3pb>=E/(B·a_l), E_<pun>=E/B，其中E为仪器测得的总能量，B为试件厚度，a_l为韧带区域长度。结果发现，根据应力状态依赖性，可将上述工程塑料分为三类：(1)PBT和PA6； (2) PBT/PPE、PPE/SBS和PA6/PPE/SBS； (3) PA6/EPR和PE6/PPE/SBS/EPR。I类塑料在一维应力集中下非常弱，III类塑料在单模态和混合三模态应力状态下都很韧。II类塑料的韧性介于两者之间。研究结果表明，本文提出的方法可用于研究工程塑料的应力状态与冲击强度的关系。还对仪器冲击试验进行了基础研究。实验分析了冲击PC Charpy试样的应变片振动信号。提出了一种在试样的冲击表面放置薄橡胶片的方法，以尽量减少包含在镖信号中的动态影响。

项目成果

J.Kusumoto, K.Arakawa, K.Takahashi: "Measurement of displacement fields around crack tip in brittle and ductile polymers" Transactions of the Japan Society of Mechanical Engineers. Vol.62, No599. 21-25 (1997)

J.Kusumoto、K.Arakawa、K.Takahashi：“脆性和延性聚合物裂纹尖端周围位移场的测量”日本机械工程师学会会刊。

M.Todo, K.Takahashi.Ph.Beuguelin, H.H.Kausch: "Effect of strain rate onm tensile fracture behavior of fiber reinforced polyamide composites" Proc.of the 11th Conf.on Composite Materials. (to appear).

M.Todo、K.Takahashi.Ph.Beuguelin、H.H.Kausch：“应变率对纤维增强聚酰胺复合材料拉伸断裂行为的影响”第 11 届复合材料会议论文集。

新川和夫,名合大輔,高橋 清: "エポキシ樹脂の動的応力拡大係数に及ぼすき裂速度・加速度効果" 日本機械学会論文集(A編). 63巻605号. 21-25 (1997)

Kazuo Shinkawa、Daisuke Naai、Kiyoshi Takahashi：“裂纹速度和加速度对环氧树脂动态应力强度因子的影响”日本机械工程学会会刊（A 版）第 63 卷，第 605 期。21-25（ 1997）

N.S.Choi, K.Takahashi: "Influence of weathring on unfilled and short-glass-fiber-filled thermoplastic polyester" Proc.of Asian Pacific Conference for Fracture and Strength '96. 561-565 (1996)

N.S.Choi，K.Takahashi：“风化对未填充和短玻璃纤维填充热塑性聚酯的影响”Proc.of Asia Pacific Conference for Fracture and Strength 96。

K.Takahashi, H.Komatsu: "Perforation characteristics of fabrics made of high strength PE fibers" Proc.of the 11th Conf.on Composite Materials. (to appear).

K.Takahashi、H.Komatsu：“高强度 PE 纤维制成的织物的穿孔特性”第 11 届复合材料会议论文集。