Experimental techniques for ductile damage characterisation

Sancho, Alexander; Cox, Michael J.; Cartwright, Tim; Aldrich-Smith, G.; Hooper, Paul A.; Davies, Catrin M.; Dear, John P.

doi:10.1016/j.prostr.2016.06.124

Cited by 11 publications

(9 citation statements)

References 18 publications

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“…An important stage in the study of the damage of a material is the measurement of that damage. There are several methods of measuring the damage in the literature [11] [12]; however, the pertinence of a method depends on the type of loading on which the material is subjected. In this work, we used a method based on the variation of the modulus of elasticity to measure the damage in the longitudinal and radial direction of sapelli and iroko, subjected to repeated compressive loading.…”

Section: Introductionmentioning

confidence: 99%

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of Entandrophragma cylindricum (Sapelli) and Chlorophora exelcia (Iroko)

Fothe¹,

Azeufack²,

Kenmeugné³

et al. 2019

WJET

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This work aims at characterizing the evolution of the damage of two tropical hardwoods. Two species from Cameroon, the Entandrophragma Cylindricum and the Chlorora Exelcia were used for the purpose. Repeated compressive loading has been made on specimens strictly selected along with longitudinal and radial directions of each species. Each cycle was made of one phase of monotonic loading and a phase of elastic release. From data obtained, we determined the variation of Young modulus and plastic deformation during each cycle of loading, and we had deduced the damage of the material. Results show that the damage appears only after a certain threshold of the plastic deformation; that damage then grows exponentially to reach a threshold after which the failure of the material occurs. As well, we noticed that the growth of damage is accompanied by the progressive decrease of the Young modulus; this confirms the deteriorating effect of the damage on the mechanical properties. Elsewhere, the damage failure threshold is less than the theoretical value, and differs from one direction to another. Finally, we noticed that the damage failure threshold of sapelli is greater than that of iroko that allows concluding that iroko gets damaged and fails more rapidly than sapelli.

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Section: Introductionmentioning

confidence: 99%

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of Entandrophragma cylindricum (Sapelli) and Chlorophora exelcia (Iroko)

Fothe¹,

Azeufack²,

Kenmeugné³

et al. 2019

WJET

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“…Then, the growth of the cavities would lead to a material local loading area decrease, which causes the non-uniformity of the stress field in the material, the dislocation aggregation, the nucleation and growth of a higher number of cavities. The cavities are interconnected forming microcracks and the macroscopic fracture eventually appeared [11,12]. The fracture morphology of the fracture zone is mainly ductile fracture along with local brittle fracture as the blanking temperature is 450-600°C, and numerous parabolic-shaped dimples and brittle fractures appear, as is shown in Fig.…”

Section: Sheared Section Surface Of Blank Partsmentioning

confidence: 90%

Fracture Characteristics of B1500HS Steel Hot Blank Parts

Hou

Lin

2018

Strength Mater

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Warm and hot blanking processes were developed for solving problems in piercing and trimming of press-hardened parts, some fine blank parts with comprehensive mechanical properties could be produced by hot blanking. To establish the optimum blanking processes and evaluate the effect of blanking temperature on the sheared section surface and fracture direction. Along with the fracture mechanism and microstructure of the parts, a series of hot blanking experiments for B1500HS steels were carried out at different blanking temperatures (450-800°C) and an 8% die clearance. The experimental results show that with the blanking temperature, the smooth (burnish) zone width increases, and the fracture direction becomes nearly normal. The sheared section surface of the parts mainly demonstrates ductile fracture mainly, accompanied by local brittle fracture over the blanking temperature range of 450-600°C. A ductile fracture region contains a great amount of fine equiaxed dimples over the blanking temperature range of 650-800°C, their microstructure is of complete martensite.

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“…In such case, the polymeric matrix (a ductile material) interacts with the high stiffness glass fiber in. Taking into consideration that the bond between the surface of the two materials is often of a low energy nature, [ 41 ] many authors in the literature [ 40,42,43 ] cite that the application of the ductile damage model is more conducive, with a better applicability of fracture.…”

Section: Numerical Proceduresmentioning

confidence: 99%

Study of the optical, thermal, morphological and mechanical characteristics of a laser weldable fiber reinforced polymer

et al. 2022

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In recent years, varied industrial users such as the automotive and electronic manufacturers, have greatly expanded the application of technical polymers, exploring the lower weight, improved moldability of complex parts and good mechanical performance that these materials can provide, especially when reinforced with fibers. Among these materials, polybutylene terephthalate reinforced with 30% glass fiber, designated as PBT GF30, is highly interesting, since it combines excellent mechanical properties with watertightness, allowing PBT GF30 to be used in the encapsulation of sensitive electronic elements. However, to maintain access, PBT GF30 products always require the use of joints, which are often created using laser welding. This work presents a detailed characterization of the thermal, optical, mechanical, and morphological characteristics of PBT‐GF30 suitable for laser welding, supported by a numerical analysis. This process allowed to determine the influence of thermal energy on the behavior of the material and thus fully understand the mechanical response of the material after laser welding. Testing of the PBT GF30 in the as received state confirmed a fusion temperature of 225°C and large energy absorption for wavelengths around 1000 nm. Exposure to large temperatures leads to increased fiber exposure and matrix degradation, with a deleterious effect on the mechanical properties. When treated at the highest temperature under consideration, the material exhibited a reduction of 66% in its ultimate tensile stress, 67% in the yield at failure, 45% in the Young's modulus and 44% in the stress intensity factor. Hardness was less affected by the temperature increase. From the numerical model for the tensile and the compact tension tests, it was possible to find a good degree of convergence. This material was generally found suitable for laser welding processes and the determined useful to support the modeling the behavior of laser welded joints.

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Experimental techniques for ductile damage characterisation

Cited by 11 publications

References 18 publications

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of <i>Entandrophragma cylindricum</i> (Sapelli) and <i>Chlorophora exelcia</i> (Iroko)

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of <i>Entandrophragma cylindricum</i> (Sapelli) and <i>Chlorophora exelcia</i> (Iroko)

Fracture Characteristics of B1500HS Steel Hot Blank Parts

Study of the optical, thermal, morphological and mechanical characteristics of a laser weldable fiber reinforced polymer

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Experimental techniques for ductile damage characterisation

Cited by 11 publications

References 18 publications

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of &lt;i&gt;Entandrophragma cylindricum&lt;/i&gt; (Sapelli) and &lt;i&gt;Chlorophora exelcia&lt;/i&gt; (Iroko)

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of &lt;i&gt;Entandrophragma cylindricum&lt;/i&gt; (Sapelli) and &lt;i&gt;Chlorophora exelcia&lt;/i&gt; (Iroko)

Fracture Characteristics of B1500HS Steel Hot Blank Parts

Study of the optical, thermal, morphological and mechanical characteristics of a laser weldable fiber reinforced polymer

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Product

Resources

About

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of <i>Entandrophragma cylindricum</i> (Sapelli) and <i>Chlorophora exelcia</i> (Iroko)

Damage Evaluation of Two Equatorial Hardwoods under Uniaxial Compression: Case of <i>Entandrophragma cylindricum</i> (Sapelli) and <i>Chlorophora exelcia</i> (Iroko)