ASTM D3039复合拉伸试验的5个考虑因素

ASTM D3039测试方法是聚合物矩阵复合拉伸试验的伟大选择，因为其在各种行业之间的可用性。

In fact, ASTM D3039 is called out by CMH17, formerly MIL-HBK-17, for determination of design allowable values for tensile strength, modulus and Poisson’s ratio.

Additionally, ASTM D3039 is used as a quality control tool for composite fiber overwrap applications. In these applications, composite overwraps are applied and cured on site to concrete columns for seismic reinforcement. Composite tensile testing provides evidence that the material has been laid up and cured per manufacturers’ instructions.

出于必要性的标准

十年前，复合材料的生产者面临着问题。yabo娱乐vip当它来测试他们的产品的力量和安全性时，唯一可用的测试方法是由塑料行业开发的标准。各种航空航天公司开发了自己的专有标准，以满足他们的需求。

To obtain tensile properties representative of the materials, and to work toward industry standardization, the ASTM D30 committee developed ASTM D3039, a consensus standard for polymer matrix composite tensile testing. Since the 1970s, this specification has grown to become the most popular composite tensile testing standard in use today.

每次ASTM D3039的复合拉伸试验的5个考虑因素

在使用ASTM D3039测试标准开始测试程序之前，有一些考虑因素可以制造，包括材料类型，面板厚度，样品加工和标签和适当的测试控制。

1.知道你的材料

ASTM D3039测试方法是特定于连续的高模量，增强聚合物基质复合材料（也就是说，含有增强纤维的聚合物材料，如碳或芳族聚酰胺）。yabo娱乐vip基质材料包括环yabo娱乐vip氧树脂，双边酰亚胺（BMIS），聚酰胺和热塑性塑料，如PEEK。

如果您的材料不连续加强，则ASTM D638通常是更适合的测试方法。同样地，陶瓷基质复合材料通常测试到ASTM C1359，以及金属至ASyabo娱乐vipTM E8。

2. Specimen Thickness

ASTM D3039 testing specimens are usually machined from flat cured panels. Ideally, the panels should be between 0.040 inches and 0.200 inches depending on the layup. Any thicker, and the specimen may fail in shear at the gripping area or internally prior to reaching the true tensile strength of the material. Any thinner, and the specimen will be unnecessarily affected by environmental factors, like the surface stress along the grips.

3. Machining of Specimens

Proper machining of ASTM D3039 testing specimens is crucial to obtaining results representative of the material, with low scatter. The specimens are rectangular with a uniform thickness cross-section. Best practice is to grind the edges of each specimen to insure parallelism and a good surface finish. The standard requires less than 64 rms, but Element generally obtains less than 20 rms.

在加工时，重要的是在纤维方向的0.5度内。由于纤维路径损坏，研磨标本厚度不合适。

4.测试标本的标签

To achieve an accurate determination of composite tensile strength, the gage area must have a nearly uniform stress distribution. The use of end tabs helps introduce the load from the grips to the specimen in a uniform way. Tabs are not always required or even desired. With carefully aligned hydraulic grips and an appropriate gripping surface, woven composites, 90 degree tape and +/- 45 degree layups may be tested more effectively without tabbing. Zero degree tape lamina specimens are best tested with tapered tabs.

无论使用的标签类型如何，测试机器夹具应延伸到样本选项卡的末端。

5.测试对准和控制

Test machine grip alignment is also critical to obtaining accurate results with ASTM D3039 testing. Generally hydraulically loaded grips are used. The alignment of the grips is adjusted and verified with a bar with 9 strain gages, assuring the loading is purely tension, without bending.

Strain may be measured with a calibrated extensometer or strain gages. Modulus is most often calculated between 1000 and 6000 microstrain. Biaxial strain measurements are used to obtain Poisson’s ratio.

可以在环境室中加热或冷却整个负载系，因此拉伸性能可以从低温温度表征达到材料的降解温度。

Final Thoughts

Choosing the right testing methods for your materials is often just as important as the results you receive. Having a working knowledge of the material type, end application, and your testing requirements will help ensure that you choose the right test methods. If you are in need of polymer matrix composite tensile testing and are considering the ASTM D3039 testing methodology, an accredited lab can help you make informed decisions, allowing you to get the most valuable insights possible. The more you know about your materials, the better they will work for you – for years to come.