Pseudo Stress Analysis Techniques

Lee, Yung–Li; Guo, Mingchao

doi:10.1016/b978-0-12-385204-5.00002-1

Cited by 7 publications

(4 citation statements)

References 7 publications

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“…Beyond the yield strength, the stress-strain relationship is highly nonlinear, so the calculated stress is not true in an absolute sense. The stress is called pseudo-stress and can be used for fatigue analysis using elastoplastic correction [43]. Yield strength indicates the start of plastic deformation, tensile strength is the maximum stress before failure, and elongation at fracture measures strain just before a force drops below 10% of the maximum during American Society of Testing and Materials (ASTM)-E8 testing.…”

Section: Elastic-plastic Materials Propertiesmentioning

confidence: 99%

“…Here, σ and ϵ are the elastic-plastic stress and strain, E the modulus of elasticity, ϵ elas the elastic strain corresponding to the pseudo stress, and K ′ and n ′ are the cyclic strength coefficient and cyclic strain hardening exponent of the elastic-plastic curve. The Smith-Watson-Topper mean stress correction formula, as shown in (10), is used to account for the mean stress effect because it is considered more promising for practical applications [28], [43]. Here, b is the fatigue strength exponent, c, the fatigue ductility exponent, σ ′ f , the fatigue strength coefficient, ϵ ′ f , the fatigue ductility coefficient, 2N f , the number of cycles till failure, σ max is the maximum stress at each cycle considering the mean stress, and ϵ a is the strain amplitude at each cycle.…”

Section: Fatigue Lifementioning

confidence: 99%

“…The fatigue material properties are generated based on the tensile strength of the material at 113°C to account for the thermal effect [43]. A fifty percent survival probability is used in fatigue simulation because of the unavailability of the standard deviation of material fatigue properties [52], [53].…”

Section: Fatigue Lifementioning

confidence: 99%

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Rotor Fatigue Life Calculation Using Constant-Amplitude Load Cycles for an Interior Permanent Magnet Synchronous Motor

Kumar Sahu,

Haddad,

Al-Ani

et al. 2024

IEEE Access

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Interior Permanent Magnet Synchronous Motors (IPMSM) are widely used as traction motors today because they can deliver high torque at low speeds, and high efficiency at low-and medium-speed ranges. Air flux barriers and bridges of an IPMSM have contradictory electromagnetic and structural requirements. The rotor undergoes a fluctuating load due to varying speeds in a drive cycle. Designing the rotor with the yield strength as a design criterion might not be sufficient. Fatigue life should be evaluated considering the mean value and amplitude of the fluctuating load profile, and the acceptance criteria should be derived based on field operations. This paper proposes a constant amplitude load cycle as an accelerated fatigue analysis approach for an IPMSM rotor and presents a fatigue analysis workflow considering the thermal and mechanical loads. It also presents the loads and boundary conditions for rotor stress analysis and the effect of elastic and elastic-plastic material properties on stress calculation.

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Section: Elastic-plastic Materials Propertiesmentioning

confidence: 99%

Section: Fatigue Lifementioning

confidence: 99%

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Rotor Fatigue Life Calculation Using Constant-Amplitude Load Cycles for an Interior Permanent Magnet Synchronous Motor

Kumar Sahu,

Haddad,

Al-Ani

et al. 2024

IEEE Access

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“…Several concepts (strain-life and stress-life) were used with consideration of the influence of the mean stress. "Morrow" -no mean stress correction [11]:…”

Section: Fig 1 Sketch Of Geometrymentioning

confidence: 99%

Review of Pressurized Vessel Structural Design – An Assessment of Total Life

Vosynek

Vlk

Návrat

2014

AMM

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Abstract. The paper discusses life prediction of pressurized cylindrical container because of its dangerous failure during usage. The fatigue of material and crack propagation were obvious from the fracture surface. Crack initiation was located in the notch root of the thread. Our goal was to review the vessel structural design based on its technical documentation. Two approaches for estimating the crack initiation period were used. As input parameters, stressstrain relations in the notch were obtained from FEM analysis, done in ANSYS Workbench. The first approach makes use of Neuber's rule based on elastic-plastic shakedown and cyclic stressstrain curve. The second concept (which is described in ČSN EN 13445-3 or AD 2000 Mekblatt S2 respectively) uses elastic shakedown. Included stress-life curves leads to the number of cycles to crack initiation. Finally the subcritical crack growth period and final fracture were estimated = the total life was evaluated.

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Influence of inertia relief analysis on the topological optimisation of unconstrained structures

Lasso Perdomo,

Orquera,

Millet

et al. 2024

Int J Interact Des Manuf

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The growth in build volumes of additive manufacturing (AM) printers has enabled the manufacture of larger and more complex products, such as drones, known as unconstrained structures. This necessitates advanced optimisation techniques to achieve optimal designs. Inertia relief (IR) is a solution for analysing these structures by leveraging their inertial properties while considering concentrated non-structural masses. Unfortunately, designers often overlook the benefits of IR due to a lack of understanding, a preference for static techniques involving boundary conditions (BCs), or the absence of a methodology for IR. Existing literature lacks sufficient comparison and documentation of the mechanical performance losses resulting from the application of BCs instead of IR. Therefore, this study provides a detailed comparison of BC and IR designs, highlighting the advantages in terms of compliance, stress fields, and eigenfrequency performance. Additionally, based on the findings, it proposes a comprehensive design and optimization methodology tailored for IR + TO, demonstrating its advantages through a case study. Applied to the redesign of a drone structure, results reveal that IR-optimized designs achieve a mass saving of 13%, with up to 53% lower compliance and 12%–32% lower stress values compared to BC-optimized designs. Those significant differences highlight the crucial role of IR in achieving optimal designs for unconstrained systems. Besides, these findings underscore the enhanced mechanical performance and potential for material savings in IR + TO, bridging the gap between theoretical understanding and practical application. This research provides valuable insights and practical guidelines for engineers and designers aiming to optimize complex structures for AM.

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Pseudo Stress Analysis Techniques

Cited by 7 publications

References 7 publications

Rotor Fatigue Life Calculation Using Constant-Amplitude Load Cycles for an Interior Permanent Magnet Synchronous Motor

Rotor Fatigue Life Calculation Using Constant-Amplitude Load Cycles for an Interior Permanent Magnet Synchronous Motor

Review of Pressurized Vessel Structural Design – An Assessment of Total Life

Influence of inertia relief analysis on the topological optimisation of unconstrained structures

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