Name: strain energy in stressed materials
Uploaded: 2024-05-23T13:00:12.000Z
Duration: 1 min 22 s
Channel: JoVE

عندما تتعرض مادة لتحميل محوري ، فإنها تتعرض لإجهاد طبيعي ، مما يؤدي إلى توليد طاقة الإجهاد. هذه المعادلة صالحة للإجهاد الموزع بشكل موحد ، وكثافة طاقة الإجهاد ثابتة في جميع أنحاء المادة.
بالنسبة للمادة ذات التوزيع غير المنتظم للإجهاد ، يتم تحديد كثافة طاقة الإجهاد للحجم الصغير للمادة.
هنا ، يتم التعبير عن كثافة طاقة الإجهاد على أنها ناتج الإجهاد المطبق والسلالة المنتجة.
يؤدي دمج كثافة طاقة الإجهاد على الحجم الكامل للمادة إلى إعطاء إجمالي طاقة الإجهاد المخزنة في المادة.
تنطبق المعادلة التي تم الحصول عليها لطاقة الإجهاد فقط على التشوه المرن وتسمى أيضا طاقة الإجهاد المرنة.
عندما تتعرض المادة للتحميل المحوري المركزي ، يفترض أن تكون الضغوط العادية موحدة على أي قسم عرضي. هنا ، يتم كتابة الإجهاد الطبيعي على أنه نسبة القوى الداخلية إلى مساحة المقطع العرضي قيد الدراسة.
تتم كتابة طاقة الإجهاد المخزنة في مثل هذه الحالات من حيث القوة الداخلية ومعامل المرونة.

طاقة الانفعال المرنة للإجهادات العادية

Elastic Strain Energy for Normal Stresses

<div style="direction: rtl;">
 تقيس طاقة الانفعال الطاقة المخزنة داخل المادة بسبب التشوه تحت ظروف التحميل، وهو مفهوم أساسي في علوم وهندسة المواد. يمكن تشكيل طاقة الانفعال عندما تتعرض المادة للتحميل المحوري مع إجهاد موزع بشكل موحد. في هذا السيناريو، يكون الضغط الذي تتعرض له المادة هو القوة الداخلية مقسومة على مساحة المقطع العرضي، ويتناسب الضغط الناتج بشكل مباشر مع هذا الضغط من خلال معامل المرونة.
 
 إذا كان توزيع الإجهاد موحدًا، فيمكن دمج كثافة طاقة الانفعال، التي يتم تعريفها على أنها منتج الإجهاد والانفعال، على كامل حجم المادة لإنتاج إجمالي طاقة الانفعال المخزنة.
 
 <img alt="Equation 1" src="/files/ftp_upload/15684/15684_Equation_1v2.svg" style="text-align: center; height: 50px;">
 ومع ذلك، يصبح حساب طاقة الانفعال أكثر تعقيدًا بالنسبة للمواد ذات توزيعات الإجهاد غير المنتظمة. في مثل هذه الحالات، يجب تحديد كثافة طاقة الانفعال للكميات الصغيرة لمراعاة التغيرات المحلية في الإجهاد والانفعال. إجمالي طاقة الانفعال هو مجموع هذه الكثافات عبر حجم المادة.
 
 <img alt="Equation 2" src="/files/ftp_upload/15684/15684_Equation_2v2.svg" style="text-align: center; height: 40px;">
 يفترض هذا الاعتبار سلوكًا مرنًا، حيث يكون التشوه قابلاً للعكس، وتعود المادة إلى الشكل الأصلي عند إزالة الحمل. يعد فهم وحساب طاقة الانفعال أمرًا حيويًا لتصميم المواد والمكونات التي يمكنها تحمل الضغوط التشغيلية دون فشل.
 
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عندما تتعرض مادة لتحميل محوري ، فإنها تتعرض لإجهاد طبيعي ، مما يؤدي إلى توليد طاقة الإجهاد. هذه المعادلة صالحة ل ...

elastic-strain-energy-for-normal-stresses

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JoVE Core

Mechanical Engineering

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Unit 1

الوحدة الأولى

Energy Methods

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KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الرئيسية

strain energy in stressed materials

Strain energy in stressed materials describes the energy stored when a material deforms under load. It is an important idea in materials science and engineering. For axial loading with a uniform stress distribution, the stress is the internal force divided by the cross-sectional area, and the strain follows from the stress through the modulus of elasticity.

When the stress is uniform, the strain energy density can be found from the product of stress and strain. That density is then integrated over the full volume of the material to calculate the total strain energy stored. This approach works for elastic behavior, where the deformation is reversible and the material returns to its original shape after the load is removed.

The calculation becomes more complex when stress is not distributed evenly. In those cases, strain energy density must be defined for small volumes so local changes in stress and strain are included. The total strain energy is then the sum of these small energy contributions across the material. This idea is useful for understanding how materials and components can handle operating stresses without failure.

Strain Energy in Stressed Materials

strain energy

Load-Deformation and Stored Strain Energy

Strain energy is the energy stored in a material when it deforms under load. It is a key idea in materials science and structural engineering. A loaded rod fixed at one end shows this clearly. When an axial force pulls on the free end, the rod stretches and stress builds inside it. As the axial force increases, the rod elongates more. This creates a direct link between the applied force and the amount of deformation. Engineers can show this relationship with a load-deformation plot. The plot...

strain-energy density

Energy Stored in Loaded Rods

Energy stored in a rod under axial load helps show how a material will respond to stretching and breaking. When the rod elongates, it stores strain energy as potential energy inside the material. Strain energy density is the amount of that energy per unit volume. In the elastic region, stress and strain have a linear relationship that follows Hooke's Law. The strain energy density in this region is found from the area under the stress-strain curve up to the elastic limit. This recoverable...

elastic strain energy for normal stresses

Strain energy in stressed materials describes the energy stored when a material deforms under load. It is an important idea in materials science and engineering. For axial loading with a uniform stress distribution, the stress is the internal force divided by the cross-sectional area, and the strain follows from the stress through the modulus of elasticity. When the stress is uniform, the strain energy density can be found from the product of stress and strain. That density is then integrated...

elastic strain energy for shearing stresses

elastic-strain-energy-for-shearing-stresses

Shear Energy Stored in Twisted Shafts

Shear energy stored in twisted shafts depends on elastic strain energy in a material. This energy is stored when a solid is deformed within its elastic limit. It comes from internal work done against the cohesive forces inside the material. When a material carries shearing stress, it also develops shearing strain. The strain energy density is the energy stored per unit volume. Within the elastic limit, stress is proportional to strain through the modulus of rigidity, so the strain energy...

impact loading

Impact Loading on a Fixed Rod

Impact loading on a fixed rod happens when a moving object strikes a stationary rod that has a uniform cross-sectional area and is fixed at one end. The impact makes the rod deform and begin to develop stress. This setup shows how a sudden hit can store energy in a structure. As the rod moves back toward its original shape, the stress rises to a maximum. At that point, the energy from the moving object has changed from kinetic energy into strain energy. Kinetic energy is the energy of motion,...

impact loading on a cantilever beam

Dropped-Weight Bending of a Cantilever Beam

Dropped-weight bending of a cantilever beam shows how impact loading changes a beam’s shape and stress. The beam has a circular cross-section and is fixed at one end. An object is dropped on the free end from a height h, so its potential energy from gravity becomes kinetic energy at impact. After the object hits the beam, the beam bends and develops a bending moment along its length. The bending is not uniform. The fixed end carries the highest strain energy, which is the energy stored in the...

castigliano&#39;s theorem

Using Strain Energy to Find Deflection

Castigliano's theorem uses strain energy to find deflection and rotation in elastic structures. Strain energy is the work done by external loads during elastic deformation. The theorem links that energy to the movement caused by the load. The key idea is simple. The partial derivative of the total strain energy with respect to a specific force gives the displacement at the point where that force acts. The same method also works for a moment, where the derivative gives the rotation at the point...

castigliano&#39;s theorem: problem solving

Beam Deflection from Central Load

Beam deflection from a central load can be found with Castigliano's theorem. The method applies to a simply supported beam with a point load at the center. It links the deflection at the load point to the strain energy stored in the beam. For this beam, the supports share the load equally. Each support carries half of the force. The bending moment at any point along the beam comes from these reactions and is written using the distance from the nearest support. Castigliano's theorem says the...

key terms and concepts

Learn how strain energy is stored in materials under load, how uniform stress is used in calculations, and why local stress changes matter.

Strain Energy in Stressed Materials | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

mechanical engineering

Strain Energy in Stressed Materials

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