Name: plane stress changes with rotation
Uploaded: 2025-05-22T09:06:18.000Z
Duration: 1 min 18 s
Channel: JoVE

Gerilim bileşenleri tarafından tanımlanan, düzlem gerilimi yaşayan bir küp üzerindeki bir noktayı düşünün.
Eleman bir açıyla dönerse, gerilim bileşenleri değişir. Bu değişiklik, eksenlerine dik yüzleri olan prizmatik bir eleman dikkate alınarak belirlenir.
Eğik yüzün alanı dikkate alınarak, dikey ve yatay yüzlerin alanları, dönme açısının trigonometrik fonksiyonları kullanılarak hesaplanabilir.
Bu yüzlere uygulanan kuvvetler temsil edilir ve elemanın üçgen yüzlerine hiçbir kuvvetin etki etmediği varsayılır. Denge denklemleri daha sonra döndürülen eksenler boyunca bileşenler kullanılarak yazılır.
Bu denklemler çözüldükten sonra normal ve kesme gerilmeleri türetilir. Normal ve kesme gerilmeleri daha sonra trigonometrik ilişkiler kullanılarak yeniden ifade edilir.
Döndürülmüş dikey eksen üzerindeki normal gerilim için bir ifade, önceki ifadelerden birindeki dönüş açısının yeni bir açı ile değiştirilmesiyle elde edilir.
Bir kübik eleman üzerine uygulanan normal gerilmelerin toplamının, elemanın yönünden bağımsız kaldığı gözlenir.

düzlem gerilmenin dönüşümü

Stres dönüşümünü incelemek, düzlem stres altındaki bir küp gibi bir malzeme içindeki stres bileşenlerinin dönmeyle nasıl değiştiğini anlamak için önemlidir. Bu değişim küpün içindeki prizmatik bir eleman dikkate alınarak analiz edilir. Eleman döndükçe, ona etki eden gerilme bileşenlerinin (hem normal hem de kayma gerilmeleri) büyüklüğü ve yönü değişir. Bu değişiklik, döndürülen elemanın yüzlerine etki eden kuvvetleri orijinal dik yüzlerine etki eden kuvvetlerle ilişkilendiren dönme açısının trigonometrik fonksiyonları kullanılarak ölçülür.

Yalnızca asal eksenlere dik yüzlerdeki kuvvetler dikkate alınarak formüle edilen denge denklemleri (üçgen yüzlerde dönme nedeniyle oluşan kuvvetler hariç), yeni gerilme bileşenlerinin türetilmesine olanak sağlar. Normal ve kayma gerilmeleri orijinal gerilmeler cinsinden yeniden ifade edilir.

<img alt="Equation 1" src="/files/ftp_upload/15652/15652_Equation_1.svg" style="height: 96px;">

Döndürülmüş dikey eksen üzerindeki normal gerilim için yeni bir ifade, önceki ifadedeki dönme açısının yeni bir ifadeyle değiştirilmesiyle elde edilir.

<img alt="Equation 2" src="/files/ftp_upload/15652/15652_Equation_2.svg" style="height: 122px;">

Bu analizin dikkate değer bir sonucu, normal gerilmelerin toplamının kübik elemanın yöneliminden bağımsız olarak değişmemesidir. Bu değişmezlik, malzemenin dış gerilimlere karşı izotropik tepkisini vurgular ve farklı yükleme koşulları altında malzeme davranışını tahmin etmek için çok önemlidir. Gerilim bileşenlerinin eleman yönelimiyle nasıl dönüştüğünü anlamak, malzeme arıza modlarını tahmin etmek ve uygulanan yüklere daha dayanıklı malzeme ve yapılar tasarlamak için hayati öneme sahiptir.

Düzlem Gerilmenin Dönüşümü

Gerilim bileşenleri tarafından tanımlanan, düzlem gerilimi yaşayan bir küp üzerindeki bir noktayı düşünün.
Eleman bir açıyla dönerse, gerilim bileşenleri değişir. ...

Education

JoVE Core

Mechanical Engineering

Makine Mühendisliği

Unit 1

Ünite 1

Transformations of Stress and Strain

Gerilme ve Şekil Değiştirme Dönüşümleri

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

Transformation of Plane Stress

plane stress changes with rotation

Plane stress changes with rotation in a material element. The analysis looks at a prismatic element inside a cube under plane stress. As the element turns, the normal stress and shearing stress on its faces change in both size and direction.

These changes are described with trigonometric functions of the rotation angle. The forces on the rotated faces are compared with the forces on the original faces that are perpendicular to each principal axis. The equilibrium equations use only the forces on those perpendicular faces, not the forces on the triangular faces created by the rotation.

From this balance, the new stress components can be written in terms of the original stresses. The normal stress on the rotated vertical axis is also found by using a new angle in a previous expression. One important result is that the sum of the normal stresses stays the same, no matter how the cubic element is oriented.

This invariant sum shows the material’s isotropic response to external stress. It helps explain how stress components shift as orientation changes. That understanding is important for predicting failure modes and for designing materials and structures that can better handle applied loads.

Plane Stress Changes with Rotation

transformation of plane stress

Plane stress changes with rotation in a material element. The analysis looks at a prismatic element inside a cube under plane stress. As the element turns, the normal stress and shearing stress on its faces change in both size and direction. These changes are described with trigonometric functions of the rotation angle. The forces on the rotated faces are compared with the forces on the original faces that are perpendicular to each principal axis. The equilibrium equations use only the forces...

principal stresses

Stress Circle for Principal and Shear Stress

The stress circle shows how normal stress and shearing stress change with angle on a transformed plane. Its center, C, lies on the vertical axis and represents the average normal stress. The radius shows the amount of stress variation as the plane rotates. Points A and B, where the circle crosses the horizontal axis, mark the maximum and minimum normal stresses. At these points, shearing stress is zero. These points define the principal stress planes, where only normal stress, called principal...

principal stresses: problem solving

Finding Principal Planes and Stress Limits

Principal planes and principal stresses are found by analyzing two planes that meet at right angles under shearing, tensile, and compressive stresses. The goal is to use the given stress values to describe how the material is loaded and to locate the planes where the stress state changes. To find the principal planes, use the formula that relates the plane angle to twice the shearing stress divided by the difference between tensile and compressive stresses. After substituting the known stress...

mohr&#39;s circle for plane stress

Reading Stress Components with Mohr's Circle

Mohr's circle is a graphical way to read the stress state at a point in a material under plane stress. It turns normal stress and shearing stress into a two-dimensional picture. This makes stress transformation easier to analyze. The method uses Cartesian coordinates. The horizontal axis shows normal stress, written as σ, and the vertical axis shows shearing stress, written as τ. Two points, A and B, are plotted from the stresses on the element. Point A is at (σx, -τxy), and point B is at (σx,...

general state of stress

Stress Tensor and Principal Stresses

The stress tensor describes the internal forces inside a material. It is used when a material is under external force or deformation. At a point such as O, the tensor can show the stress components on any plane through that point. A tetrahedral element helps show how these forces act. One face, XYZ, is perpendicular to the line OA. The other faces line up with the coordinate axes, and point O is the origin. The stress on the tetrahedron is split into normal and shear components on each face. <br...

yield criteria for ductile materials under plane stress

yield-criteria-for-ductile-materials-under-plane-stress

Tresca and Von Mises Yield Criteria

Ductile materials can yield when they are loaded beyond a safe stress level. Engineers use yield criteria to check whether structural elements and machine parts can handle the expected load without permanent deformation. The yield point is first found with a tensile test, which measures how the material responds to uniaxial stress. A tensile test is not enough when a part faces biaxial or plane stress conditions. In those cases, more advanced criteria are needed to predict failure. One common...

transformation of plane strain

Plane Strain Under Rotated Axes

Plane strain changes when the coordinate axes are rotated. This matters for long bars and similar elongated structures that are loaded uniformly on their sides. In these members, one dimension is much larger than the others, so deformation is mainly studied in a single plane. At a point such as O, the key strain components lie along the x and y axes. The strain along the z-axis is negligible in plane strain. Together, the x and y strain components describe the deformation state in the xy-plane.

mohr&#39;s circle for plane strain

Principal and Shear Strains on Mohr’s Circle

Mohr’s circle for plane strain shows how normal strain and shear strain change on a graph. The horizontal axis is normal strain, written as ε, and the vertical axis is shear strain, written as γ. It uses two plotted points, X and Y, to represent the strain state. Point X has coordinates (εx, -γXY), and point Y has coordinates (εY, γXY). The center of the circle, O, gives the average normal strain. The radius comes from the relationship between normal strain and shear strain, so the circle...

three-dimensional analysis of strain

Principal Strain Directions in 3D

Three-dimensional strain analysis shows how a material changes shape when it is loaded. It is especially useful for elastic, homogeneous materials. A small cubic element inside the material can expand or contract along principal stress axes. That change turns the cube into a rectangular parallelepiped, which makes the deformation easier to picture. The principal stress axes are orthogonal, or at right angles to each other. Along these directions, the stress does not create shear inside the...

measurements of strain

How Strain Gauges Measure Deformation

Strain describes how a material deforms when a force is applied. Normal strain compares the change in length with the original length. Engineers use this measure to track stretching or compression in materials. For higher accuracy, they often use electrical strain gauges. A strain gauge has a conductive wire on a paper backing that sticks to the surface of the material. It works through the piezoresistive effect, which means the wire’s electrical resistance changes when the material is bent,...

key terms and concepts

See how normal and shearing stress change as a plane-stressed element rotates, and why the sum of normal stresses stays constant for any orientation.

Plane Stress Changes with Rotation | JoVE K12

JoVE Core Makine Mühendisliği, denge, kuvvetler, kafes kiriş analizi ve yapısal mekanik gibi temel konuları kapsayan kısa, anlaşılması kolay animasyonlu videolar sunar. Gerçek dünyadaki uygulamalarını keşfedin ve bilim insanlarının önderlik ettiği deneylerle bu kavramların uygulanmasına tanık olun.

mechanical engineering

Plane Stress Changes with Rotation

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