5 Considerations for ASTM D3039 Composite Tensile 测试

The ASTM D3039 testing methodology is a great choice for polymer matrix 复合材料拉伸试验 because of its usability across a wide range of industries.

事实上, ASTM D3039由CMH17命名, 以前MIL-HBK-17, for the determination of design allowable values for 抗拉强度、模量和泊松比.

Additionally, ASTM D3039 is used as a quality control tool for composite fiber overwrap applications. 在这些应用中, composite overwraps are applied and cured on-site to concrete columns for seismic reinforcement. 复合材料拉伸试验 provides evidence that the material has been laid up and cured per manufacturers’ instructions.

ASTM D3039 -一个标准诞生于必要

几十年前，生产商 复合材料 遇到了问题. When it came time to test their products for strength and safety, the only available test methods were standards developed by and for the plastics industry. Various aerospace firms developed their own proprietary standards to meet their needs.

To obtain tensile properties representative of the materials, 并努力实现im体育平台app下载标准化, ASTM D30委员会制定了ASTM D3039, a consensus standard for polymer matrix 复合材料拉伸试验. Since the 1970s, this specification has grown to become the most popular 复合材料拉伸试验 目前使用的标准. 

5 Considerations for Composite Tensile 测试 per ASTM D3039

Before embarking on a testing program using the ASTM D3039 testing standard, 有几点需要考虑, 包括材料的类型, 面板厚度, 试样加工和压边, 适当的测试控制.

1. 了解你的材料

The ASTM D3039 testing methodology is specific to continuous high-modulus, reinforced polymer matrix composites (that is to say, polymeric materials that contain reinforcing fibers, 比如碳或芳纶). Matrix materials include epoxies, bismaleimides (BMIs), polyamides, and thermoplastics such as PEEK.

If your material is discontinuously reinforced, ASTM D638 generally is a better-suited test method. 同样的, ceramic matrix 复合材料 are generally tested to ASTM C1359, 和金属符合ASTM E8.

2. 试样厚度

ASTM D3039 testing specimens are usually machined from flat-cured panels. 理想情况下，面板应该在0之间.040英寸和0.200英寸取决于上篮. 任何厚, and specimen may fail in shear at the gripping area or internally prior to reaching the true 抗拉强度 of the material. 任何稀释剂, and specimen will be unnecessarily affected by environmental factors, 比如握把的表面应力.

3. 试件的加工

Proper machining of ASTM D3039 testing specimens is crucial to obtaining results representative of the material, 低散射. The specimens are rectangular with a uniform thickness cross-section. The 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 im体育APP generally obtains less than 20 rms.

加工时，重要的是在0以内.纤维方向5度. Grinding specimens to thickness is not appropriate due to fiber path damage.

4. 试验标本的标签化

To achieve an accurate determination of composite 抗拉强度, 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. 标签页并不总是必需的，甚至不总是需要的. With carefully aligned hydraulic grips and an appropriate gripping surface, 编织复合材料, 90度的磁带, and +/- 45-degree layups may be tested more effectively without tabbing. Zero-degree tape lamina specimens are best tested with tapered tabs.

不管所使用的选项卡类型如何, the test machine grips should extend past the end of the specimen tabs.

5. 测试校准与控制

Test machine grip alignment is also critical to obtaining accurate results with ASTM D3039 testing. 通常使用液压加载握把. The alignment of the grips is adjusted and verified with a bar with 9 strain gages, 确保载荷为纯张力, 没有弯曲.

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

The entire load train may be heated or cooled in an environmental chamber so the tensile properties can be characterized from 低温下 直至材料的降解温度. 

ASTM D3039测试的元件优势

Choosing the right testing methods for your materials is often just as important as the results you receive. 具有材料类型的工作知识, 结束应用程序, and testing requirements will help ensure that you choose the right test methods. 如果你需要 聚合物基复合材料测试 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. 

了解更多信息 今天就im体育APP的专家.