--- title: "Blog LabsCubed | What is Tensile Testing & Why it Matters in Materials Labs" description: "This article introduces tensile testing, its applications, common laboratory challenges, and practical solutions for obtaining accurate results." url: https://labscubed.com/post/what-is-tensile-testing-and-why-it-matters --- ![What is Tensile Testing & Why it Matters in Materials Labs](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/what-is-tensile-testing-and-why-it-matters/Screenshot-2025-07-07-at-3.54.04-PM.png) # What is Tensile Testing & Why it Matters in Materials Labs [Home](https://labscubed.com/) [Blog](https://labscubed.com/blog) What is Tensile Testing & Why it Matters in Materials Labs [Lab Automation](https://labscubed.com/blog/category/lab-automation) July 18, 2025 8 min ## An Introduction to Tensile Testing Have you ever wondered if the material chosen for a project is well-suited for a product's application? Luckily, **material testing** allows for benchmarking a material's performance under certain load conditions. This helps designers choose the proper materials without overdoing it on the performance side, ultimately saving money by selecting the appropriate material. It also allows for quantitatively comparing the physical properties of dissimilar materials. ‍**Tensile testing** is a way to understand a material's mechanical properties. It works by pulling a material until it breaks, showing its **strength (ultimate tensile strength)**, **stretchiness (elongation)**, and **stiffness (modulus of elasticity)**. This test is useful in material science, engineering, and especially for quality control in plastics.  This article introduces tensile testing, its applications, common laboratory challenges, and practical solutions for obtaining accurate results. Fig. 1 illustrates an automated tensile test performed using the CubeOne system. ![__wf_reserved_inherit](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/what-is-tensile-testing-and-why-it-matters/gif-cubeone-rubber-tensile-test-ezgif.com-optimize-1-.gif) _Figure 1: Automated rubber tensile testing (ASTM D412) using the CubeOne_ ‍ ## **What is Tensile Testing?** **Tensile testing** is a fundamental mechanical test where a material specimen is pulled until it breaks, revealing how it reacts to stretching forces. This process provides crucial data like **stress**, **strain**, and **elongation**, from which key material properties such as **ultimate tensile strength**, **yield strength**, and **modulus of elasticity** are determined. ### **Key Principles and How it Works** Testing relies on standardized methods:
Specimen Preparation:Materials are shaped into precise "dog-bone" or "dumbbell" forms (e.g., following ASTM D638 for plastics or ASTM D412 for rubbers) to support consistent testing procedures. The gauge length is a specific, pre-defined section of the specimen where deformation is measured.
Tensile Testing Machine:A universal testing machine (UTM) uses a load frame, grips to hold the specimen, a load cell to measure force, and an extensometer to measure elongation.
Video ExtensometerThe specimen is clamped, a controlled pulling load is applied at a constant rate, and data is continuously recorded until fracture.
### ‍**Understanding Engineering Stress and Strain** For most practical applications, **engineering stress (σe​)** and **engineering strain (εe​)** are used. They are both calculated based on the original dimensions of the specimen's gauge length: **Engineering Stress:** Applied load divided by original cross-sectional area.  ![(Applied load divided by original cross-sectional area).](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/what-is-tensile-testing-and-why-it-matters/AD_4nXcguUm35VYWGDKZcwTfWOPbRPrxLlKYQci1jCNqxeL5dDKv5jsTOEG5q_RMWkJ6taAGhWv0Ujpu22TVNobqpRT8Mujj3DntnJe-yarckj_THagcsEqfW0xL6BhwRtsKukTgkEm1VQ.png) ‍**Engineering Strain:** Change in length measured by extensometer divided by original gauge length ![Change in length measured by extensometer divided by original gauge length](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/what-is-tensile-testing-and-why-it-matters/AD_4nXeRxkGm-KcO636VGgtNR6HsjL9-BgiAtUGXzbTpDCIU5EQ7o4HfDDXLYhxws1XGbP4C4Eywpsk8K3hNrT2Y1FeswsJdXtQvsWJvn-pPmPOBlE51bqAMRpYD4iofOU1ME9eE2KtdIA.png) ### ‍**Key Material Properties Measured** A **stress-strain curve** is plotted from the data, illustrating the material's behavior. On this curve, **strain is plotted on the X-axis** and **stress on the Y-axis**, revealing: - **Ultimate Tensile Strength (UTS):** The maximum stress the material withstands before fracturing. - **Yield Strength:** The stress at which permanent (plastic) deformation begins.  - **Fracture Stress/Strength:** The stress on the material at the exact moment of fracture. - **Elongation at Break:** The percentage increase in length at fracture, indicating **ductility**.  - **Strain at Break:** The strain value on the stress-strain curve at the point of fracture, representing the total deformation undergone before breaking.  - **Young's Modulus (Modulus of Elasticity):** A measure of the material's **stiffness** or resistance to elastic deformation. If using a CubeOne or CurbeTen system, all test results can be reviewed, compared, and exported via the **LabsCubed Portal**, seen in Fig. 2. ![__wf_reserved_inherit](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/what-is-tensile-testing-and-why-it-matters/D412_example_labsportal.png) Figure 2: Labscubed Portal and overview of collected sample data for rubber tensile testing (ASTM D412). ### **Understanding Stress-Strain Curves Across Material Types** The interpretation of stress-strain curves varies depending on the material type and applicable testing standard. For **rigid materials** such as metals or thermoplastics (e.g., tested under [ASTM D638](https://labscubed.com/resources/astm-d638-iso-527-2-plastic-tensile-testing)), the curve is typically divided into two regions: - an **elastic region** (the most linear section at the start of the test), where the material returns to its original shape after the load is removed, and - a **plastic region**, where permanent deformation begins. The **transition point between these regions** is defined as the **yield point** (or **yield stress**), often determined using a 0.2% offset method. This method finds the yield point by drawing a line parallel to the elastic region of the curve, offset by a small strain (commonly 0.2%). The yield point is critical for assessing when a material will begin to deform irreversibly under load. In contrast, **elastomers and rubbers** (e.g., tested under [ASTM D412](https://labscubed.com/resources/astm-d412-iso-37-rubber-tensile-testing)) behave quite differently. These materials are highly **hyperelastic** and may stretch several hundred percent without permanent deformation. Their stress-strain curves do **not typically exhibit a distinct plastic region or clear yield point**. Instead, they remain elastic until they break, often **failing directly from the elastic phase**. As a result, standards like [ASTM D412](https://labscubed.com/resources/astm-d412-iso-37-rubber-tensile-testing) emphasize **tensile stress at specific elongation levels** (e.g., 100%, 200%, 300%) rather than defining yield stress. This approach enables comparison of material stiffness and rigidity under large, reversible deformations. ### **Validating Test Results: The Importance of Gauge Length Failure** For valid results, the specimen **must fracture within its gauge length**. If breakage occurs outside this area (e.g., at the grips), the test is considered **inconclusive** and must be re-performed, as improper gripping or stress concentrations likely influenced the failure. Fig. 3 shows an example of an out-of-gauge failure in a 3D-printed [ASTM D638](https://labscubed.com/resources/astm-d638-iso-527-2-plastic-tensile-testing) tensile specimen. ![__wf_reserved_inherit](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/what-is-tensile-testing-and-why-it-matters/out-of-gauge-failure-ASTMD638-tensile-sample.png) _Figure 3: Example of out-of-gauge failure using ASTM D638 tensile sample (3D printed Nylon 6 CF)._ ## **Where is Tensile Testing Used?** Tensile testing is a key tool used across many industries. It helps make sure materials are strong enough and products work as they should. It's essential for: | Category | Description | | --- | --- | | Quality Control (QC) | To confirm materials and products meet required standards or performance expectations. | | Failure Analysis | To investigate why a component or product failed by assessing the mechanical properties of the degraded material. | | Designing Products | To pick the right materials so products can handle what they're built for. | | Developing New Materials (R&D) | To check how new materials perform and compare them to others. | Tensile testing provides key mechanical property data used in industries like automotive, consumer goods, composites, and additive manufacturing for material selection and quality control. | Category | Description | | --- | --- | | Automotive | For materials used in dashboards, bumpers, and interior components, verifying their strength and durability for safety and longevity. | | Consumer Goods | Assessing the materials in everything from toys to appliances and electronics to ensure they are robust, safe, and long-lasting. | | Composite Materials | Assessing the strength of both the base material matrix and the reinforcing fibers in composite structures. | | Additive Manufacturing (3D Printing) | Characterizing the mechanical properties of 3D-printed parts, which can vary significantly from traditionally manufactured counterparts. | Sticking to [ASTM](https://store.astm.org/)/[ISO](https://www.iso.org/standards.html) tensile standards for various materials is crucial. This guarantees reliable, comparable test results, simplifying material selection for different use cases. ## **Lab Challenges in Tensile Testing & Solutions** Tensile testing presents several common challenges in laboratory environments, including specimen variability, equipment accuracy, human error, data interpretation, and the costs associated with tools and high test volumes. Additionally, handling complex materials, like soft rubbers or high-strength plastics, can further complicate the process. These hurdles, outlined in Table 1 below, can significantly impact test consistency and throughput. One powerful way to mitigate these issues is through automation. [**CubeOne (for rubbers and elastomers)**](https://labscubed.com/rubber-testing) **and** [**CubeTen (for plastics)**](https://labscubed.com/plastic-testing) are automated tensile testers developed by LabsCubed (Fig. 4), specifically designed to tackle these challenges head-on and deliver precise, repeatable, and efficient results. ‍ ![__wf_reserved_inherit](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/what-is-tensile-testing-and-why-it-matters/cubeone-cubeten-labscubed-automation-tensile-testing.png) _Figure 4: LabsCubed automated systems._ Here are some common hurdles in tensile testing and how LabsCubed automation systems solve them. | Challenge | Description | How LabsCubed Automated Systems Provide Solutions | | --- | --- | --- | | Specimen Quality | Getting samples with the right dimensions, smooth surfaces, and no flaws is tough. Brittle or very soft materials are especially tricky to prepare correctly. | Automated Measurement: CubeTen and CubeOne automatically measure sample thickness (and width for CubeTen) with calibrated sensors, eliminating manual errors and improving consistency from varying sample prep. | | Machine Uptime & Accuracy | Machines need regular checks and calibration to give correct force and movement readings. Worn parts like grips and extensometers can also throw off results. | Precision Measurement Systems: Both CubeOne and CubeTen use precision crosshead displacement and offer automated physical or video extensometers (for precise, non-contact strain) to ensure accurate, ASTM-calibrated force and deformation readings. | | Human Error | Mistakes in how samples are loaded, gripped, or how data is read can lead to bad results. Everyone needs consistent training and clear steps. | Full Automation: Systems automate specimen alignment, gripping, and measurement. This removes human variability in positioning, gauge length marking, and clamping pressure, ensuring consistent inputs and results across operators and shifts. | | Data Understanding | Interpreting the stress-strain curve, especially finding specific points like yield for some materials, can be complex. Knowing what the data truly means takes skill. | LabsCubed Portal: Offers interactive stress-strain visualization, batch reports, and easy data export (CSV, PDF). It also integrates with other lab systems (LIMS, ERP) for streamlined analysis and easier interpretation of complex material behaviors. | | Equipment & Tool Costs | Buying and maintaining tensile testing machines, plus the ongoing cost of grips and tools for preparing samples, can be expensive. | Maximized ROI & Efficiency: By automating repetitive tasks, CubeOne saves up to 85% of team time. This optimizes technician time for higher-value work, accelerating results and improving return on investment over manual methods. | | High Test Volume | For busy labs, running many tests efficiently and handling all the data quickly can be a big challenge. | Increased Throughput: CubeOne handles up to 12 samples, and CubeTen handles up to 15 samples at a time (Fig. 5). This high capacity, combined with automation, drastically increases testing efficiency and throughput for busy labs. | | Gripping Complex Materials | Holding a wide range of materials and shapes firmly without them slipping or breaking prematurely at the grips requires specialized solutions. | Smart Alignment & Gripping: CubeTen features a smart vision system to detect specimen edges and automatically aligns each sample with precision in the grips, using self-centering mechanisms. This minimizes slippage and premature failure, even with varied material shapes and surface finishes. | ## Conclusion Tensile testing remains a cornerstone of material science, indispensable for ensuring product quality, safety, and innovation, especially with plastics and rubbers. While traditional methods present challenges, modern automation provides clear solutions.  LabsCubed's [CubeOne](https://labscubed.com/rubber-testing) and [CubeTen](https://labscubed.com/plastic-testing) automated tensile testers are designed to tackle these hurdles head-on. By delivering precision, consistency, and efficiency, these systems can help labs overcome common issues and optimize their material testing workflows. Watch the video below to discover how LabsCubed's [CubeTen](https://labscubed.com/plastic-testing) automates plastic testing in labs, saving 90% of time in repetitive lab tasks and providing 40% more data consistency. ## Keep reading [![Universal testing machine with a necked plastic dumbbell specimen held in wedge grips](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/universal-testing-machine-guide-plastics-rubber/universal-testing-machine-thumb.webp) Tensile Testing Lab Automation 9 min read ### Universal Testing Machine: Complete Guide to Specifications, Applications & Automation Learn how a universal testing machine works, what tests it performs, key specifications to evaluate, and how automation improves materials testing workflows.](https://labscubed.com/post/universal-testing-machine-guide-plastics-rubber)[![Tensile Strength Tester: A Buyer's Guide for QA Labs](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/tensile-strength-tester-buyers-guide/Thumb---Universal-Testing-Machine-Guide---Labscubed-Blog.webp) Tensile Testing Lab Automation 9 min read ### Tensile Strength Tester: A Buyer's Guide for QA Labs Choose the right tensile strength tester for plastics or rubber QA. Compare manual vs. automated systems, key specs, and ROI. Get a quote from LabsCubed.](https://labscubed.com/post/tensile-strength-tester-buyers-guide)[![Universal testing machine for rubber - LabsCubed benchtop tester and a specimen tray being loaded by hand](https://grozewxrymeiruhggcdy.supabase.co/storage/v1/object/public/blog-images/blog/universal-testing-machine-for-rubber-buyers-guide/6a6c62dd54cb89fa0482971a_Thumbnail--20Universal-20Testing-20Machine-20for-20Rubber-20LabsCubed-20Blog.webp) Lab Automation 9 min read ### Universal Testing Machine for Rubber: 2026 Buyer Guide Choose a universal testing machine for rubber: grips, force ranges, and automated workflows that cut variability. See how LabsCubed automates rubber QA.](https://labscubed.com/post/universal-testing-machine-for-rubber-buyers-guide) ## Building the Autonomous Tensile Lab. We build the automated systems that bring true autonomy to tensile testing. Remove repetitive manual work from your workflows and empower your lab to run around the clock with precision. [Get a Quote](https://labscubed.com/get-a-quote) ![LabsCubed](https://labscubed.com/assets/img/logo.webp) Company [Home](https://labscubed.com/) [Rubber Testing](https://labscubed.com/rubber-testing) [Plastic Testing](https://labscubed.com/plastic-testing) Help [FAQs](https://labscubed.com/#faqs) [Get a Quote](https://labscubed.com/get-a-quote) Access [Request Demo](https://labscubed.com/get-a-quote) [Privacy Policy](https://labscubed.com/privacy-policy) Contact [info@labscubed.com](mailto:info@labscubed.com) [(519) 749-0460](tel:+15197490460) Kitchener, ON © 2026 LabsCubed Inc. All rights reserved.