Herman Jacobus Cornelis Voorwald
Sao Paulo State University
Composite numberUltimate tensile strengthFatigue limitBagasseThermal sprayingComposite materialEpoxyMetallurgyMaterials scienceWeldingCorrosionScanning electron microscopeCelluloseAlloyCoatingResidual stressElectroplatingFiberShot peeningThermogravimetric analysisPeening
124Publications
23H-index
2,373Citations
Publications 124
Newest
#1Fillip Cortat Alves (UNESP: Sao Paulo State University)
#2Francisco Maciel Monticeli (UNESP: Sao Paulo State University)H-Index: 7
Last. Heitor Luiz Ornaghi (Universidade Federal da Integração Latino-Americana)H-Index: 16
view all 6 authors...
Abstract This study aimed to evaluate the dynamic mechanical properties and the creep behavior of glass/epoxy composites containing different void contents. A 3D reconstruction using X-ray microtomography (MCT) was done to determine void content, position, and morphology. Moreover, dynamic mechanical analysis over a wide temperature range and creep tests using different temperatures (from 30 °C to 210 °C) and stress levels (1, 5, and 10 MPa) were conducted. It was found that the void content int...
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#1Anne Shayene Campos de Bomfim (UNESP: Sao Paulo State University)H-Index: 2
#2Herman Jacobus Cornelis Voorwald (UNESP: Sao Paulo State University)H-Index: 23
Last. Maria Odila Hilário Cioffi (UNESP: Sao Paulo State University)H-Index: 22
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Abstract This work was based on sustainable principles by reusing the post-consumer waste espresso coffee capsules as raw material for a novelty composite, which should perform well concerning mechanical and thermal properties for a home composter product application, substituting neat polymers. Plastic components were mechanically recycled and mixed with dried coffee grounds, then 20 and 30 wt% reinforced composites with and without coupling agent were injected into specimens. Thermal analysis ...
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#1Francisco Maciel Monticeli (UNESP: Sao Paulo State University)H-Index: 7
#2Midori Yoshikawa Pitanga (UNESP: Sao Paulo State University)H-Index: 1
Last. Herman Jacobus Cornelis Voorwald (UNESP: Sao Paulo State University)H-Index: 23
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#1Midori Yoshikawa Pitanga (UNESP: Sao Paulo State University)H-Index: 1
#2Maria Odila Hilário Cioffi (UNESP: Sao Paulo State University)H-Index: 22
Last. Chun H. Wang (UNSW: University of New South Wales)H-Index: 55
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Abstract The increase in composites usage for primary and secondary structural components demands advanced repair techniques such as doubler, multi-step, and scarf to restore a damaged structure to its original design capability. Currently, most scarf repairs employ a straight taper at a typical ratio ranging between 1:20 to 1:60 to attain the original design strength. This paper aims to present a new method for reducing the footprint of scarf repairs by optimizing the taper profile through the ...
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#1Kelly Cristina Coelho de Carvalho Benini (UNESP: Sao Paulo State University)H-Index: 8
#2Heitor Luiz Ornaghi (UNESP: Sao Paulo State University)H-Index: 16
Last. Maria Odila Hilário Cioffi (UNESP: Sao Paulo State University)H-Index: 22
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The effects of chemical treatment sequences on the chemical, physical, and mainly the thermal properties of Imperata Brasiliensis grass in the process used to obtain cellulose fibers were analyzed. The thermal properties were extensively investigated by a thermogravimetric analysis, and a thermal behavior prediction was carried out using kinetic parameters and simulation. Thermal simulations using statistical tools enable thermal predictions for any material under different conditions. However, ...
3 CitationsSource
#1Francisco Maciel Monticeli (UNESP: Sao Paulo State University)H-Index: 7
#2David Daou (University of Belgrade)H-Index: 1
Last. Maria Odila Hilário Cioffi (UNESP: Sao Paulo State University)H-Index: 22
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Abstract The aim of this study was to carry out simulations and perform experimental quasi-static delamination tests in modes I and II to characterize the mechanical behavior at a hybrid interface. For that purpose, contact angle, infrared spectroscopy, and energy balance model results were obtained to characterize the physical interfacial energy behavior. The simulations and experimental tests presented similar values and trends, indicating that this is a viable method for predicting the critic...
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#1Francisco Maciel Monticeli (UNESP: Sao Paulo State University)H-Index: 7
#2Marcos Yutaka Shiino (UNESP: Sao Paulo State University)H-Index: 7
Last. Maria Odila Hilário Cioffi (UNESP: Sao Paulo State University)H-Index: 22
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Abstract The adoption of carbon/glass fiber hybrid composites is an economical alternative to high-cost carbon/epoxy composites and helps to address environmental issues. However, the addition of another type of fiber modifies the mechanical behavior of the composite regarding interfacial interactions, consequently affecting other properties. Research related to three interfaces, with regard to hybrid composites, has not yet provided a good understanding of the physical interactions between comp...
1 CitationsSource
#1Roberto Ferreira Motta (UNESP: Sao Paulo State University)
#2René Alderliesten (TU Delft: Delft University of Technology)H-Index: 31
Last. Herman Jacobus Cornelis Voorwald (UNESP: Sao Paulo State University)H-Index: 23
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Abstract Current models for delamination propagation prediction in fiber-reinforced polymer (FRP) composites exhibit limitations to explain the physics underlying the mechanisms of damage formation in fatigue. In order to contribute in this field, this research focuses on the study of damage development within a single loading cycle of FRP double cantilever beam specimens under different stress ratios (R). The acoustic emission technique was used to investigate damage propagation. Results showed...
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#1Thatiane Brocks (UNESP: Sao Paulo State University)H-Index: 5
#2Heitor Luiz Ornaghi (UNESP: Sao Paulo State University)H-Index: 16
Last. Maria Odila Hilário Cioffi (UNESP: Sao Paulo State University)H-Index: 22
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Abstract In this study, a model of fatigue life estimative based on dynamic mechanical analysis and fatigue tests is validated. Storage modulus is the viscoelastic parameter which better correlate with fatigue resistance. Accordingly, it was proposed a fatigue life estimative based on the extension of the storage modulus in function of time and its relation with the parameters of the equation which defines strength versus number of cycles (S-N) curve. A new correlation between viscoelastic prope...
2 CitationsSource
#1Heitor Luiz Ornaghi (UNESP: Sao Paulo State University)H-Index: 16
#2Francisco Maciel Monticeli (UNESP: Sao Paulo State University)H-Index: 7
Last. Herman Jacobus Cornelis Voorwald (UNESP: Sao Paulo State University)H-Index: 23
view all 6 authors...
Abstract The creep behavior of hybrid carbon/glass laminate composites was investigated using a dynamic mechanical analyzer and different temperature profiles. Dynamic analysis and porosity were carried out prior to the creep test applying Findley's power law. The dynamic curves were not influenced by porosity but were affected by the architecture of the composites. The creep tests showed porosity dependence at temperatures below Tg while at higher temperatures, the architecture of the reinforce...
8 CitationsSource