scholarly journals Identifying the weak spots in packaging paper: local variations in grammage, fiber orientation and density and the resulting local strain and failure under load

Cellulose ◽  
2020 ◽  
Vol 27 (17) ◽  
pp. 10327-10343 ◽  
Author(s):  
Jussi Lahti ◽  
Michael Dauer ◽  
D. Steven Keller ◽  
Ulrich Hirn
Keyword(s):  
Fiber Orientation ◽  
Tensile Testing ◽  
Local Density ◽  
Tensile Load ◽  
Local Strain ◽  
Local Deformation ◽  
Material Failure ◽  
Bond Failure ◽  
Paper Structure ◽  
Local Fiber

AbstractMeasured local paper structure—i.e. local basis weight, local thickness, local density and local fiber orientation—has been linked to local strain and local material failure (local temperature increase due to energy dissipation upon fiber–fiber bond failure) measured during tensile testing. The data has been spatially linked through data map registration delivering several thousand $$1\times 1\,\hbox{mm}^2$$ 1 × 1 mm 2 paper regions, each containing all measured properties. The relation between local paper structure and resulting local deformation and failure is studied with regression models. Multiple linear regression modeling was used to identify the paper structure related drivers for local concentrations of strain under load and local concentrations of material failure, which are both starting to occur considerably before rupture of the paper. Analyzing the development of local strain in paper we found that regions with higher basis weight and higher fiber orientation in load direction tend to exhibit considerably lower strain during tensile testing. Furthermore, the relation between local strain and local grammage can be predicted with the statistical theory of elasticity. Also regions with higher density have lower local strain, but not as pronounced. The findings for local fiber–fiber bond failure of paper are similar but not equivalent. The strongest correlation exists with local grammage. Local density and local fiber orientation show in turn weaker correlation with local bond failure. Local variations in paper thickness were not relevant in any case. These findings are highlighting the relevance of local fiber orientation and local density variations as structural mechanisms governing paper failure. In the past the focus has been mostly on paper formation. Together with local grammage (formation) they are responsible for the weak spots in paper, and thus cause local concentrations of paper strain and the initiation of failure under tensile load.

scholarly journals Studying the Damage Evolution and the Micro-Mechanical Response of X8CrMnNi16-6-6 TRIP Steel Matrix and 10% Zirconia Particle Composite Using a Calibrated Physics and Crystal-Plasticity-Based Numerical Simulation Model

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 759
Author(s):  
Faisal Qayyum ◽  
Sergey Guk ◽  
Ulrich Prahl
Keyword(s):  
Simulation Model ◽  
Crystal Plasticity ◽  
Mechanical Response ◽  
Tensile Load ◽  
Local Strain ◽  
Tensile Tests ◽  
Local Deformation ◽  
Zirconia Particle ◽  
Steel Matrix ◽  
Damage Criterion

The mechanical behavior of newly developed composite materials is dependent on several underlying microstructural phenomena. In this research, a periodic 2D geometry of cast X8CrMnNi16-6-6 steel and 10% zirconia composite is virtually constructed by adopting microstructural attributes from literature. A physics-based crystal plasticity model with ductile damage criterion is used for defining the austenitic steel matrix. The zirconia particles are assigned elastic material model with brittle damage criterion. Monotonic quasi-static tensile load is applied up to 17% of total strain. The simulation results are analyzed to extract the global and local deformation, transformation, and damage behavior of the material. The comprehensively constructed simulation model yields the interdependence of the underlaying microstructural deformation phenomena. The local results are further analyzed based on the interlocked and free regions to establish the influence of zirconia particles on micro-mechanical deformation and damage in the metastable austenite matrix. The trends and patterns of local strain and damage predicted by the simulation model results match the previously carried out in-situ tensile tests on similar materials.

Cross Weld Tensile Testing With Digital Image Correlation to Determine Local Strain Response

2021 ◽  
Author(s):  
William Siefert ◽  
James Rule ◽  
Boian Alexandrov ◽  
Jorge Penso ◽  
Michael P. Buehner
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Tensile Testing ◽  
Local Strain ◽  
Image Correlation ◽  
Strain Response

scholarly journals Oriented collagen fibers direct tumor cell intravasation

2016 ◽  
Vol 113 (40) ◽  
pp. 11208-11213 ◽  
Author(s):  
Weijing Han ◽  
Shaohua Chen ◽  
Wei Yuan ◽  
Qihui Fan ◽  
Jianxiang Tian ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Extracellular Matrix ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Fiber Orientation ◽  
Breast Cancer Cells ◽  
Protein Concentration ◽  
Collagen Fiber ◽  
Fiber Alignment ◽  
Local Fiber

In this work, we constructed a Collagen I–Matrigel composite extracellular matrix (ECM). The composite ECM was used to determine the influence of the local collagen fiber orientation on the collective intravasation ability of tumor cells. We found that the local fiber alignment enhanced cell–ECM interactions. Specifically, metastatic MDA-MB-231 breast cancer cells followed the local fiber alignment direction during the intravasation into rigid Matrigel (∼10 mg/mL protein concentration).

scholarly journals Alterations in Microstructure and Local Fiber Orientation of White Matter Are Associated with Outcome after Mild Traumatic Brain Injury

2020 ◽  
Vol 37 (24) ◽  
pp. 2616-2623
Author(s):  
Mehrbod Mohammadian ◽  
Timo Roine ◽  
Jussi Hirvonen ◽  
Timo Kurki ◽  
Jussi P. Posti ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Mild Traumatic Brain Injury ◽  
Fiber Orientation ◽  
Local Fiber

Region-of-Interest X-Ray Tomography for the Non-Destructive Characterization of Local Fiber Orientation in Large Fiber Composite Parts

2019 ◽  
Vol 809 ◽  
pp. 587-593
Author(s):  
Simon Zabler ◽  
Katja Schladitz ◽  
Kilian Dremel ◽  
Jonas Graetz ◽  
Dascha Dobrovolskij
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Fiber Orientation ◽  
Fiber Composite ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Anisotropic Thermal Conductivity ◽  
Local Fiber

To detect and characterize materials defects in fiber composites as well as for evaluatingthe three-dimensional local fiber orientation in the latter, X-ray micro-CT is the preferred methodof choice. When micro computed tomography is applied to inspect large components, the method isreferred to as region-of-interest computed tomography. Parts can be as large as 10 cm wide and 1 mlong, while the measurement volume of micro computed tomography is a cylinder of only 4 − 5 mmdiameter (typical wall thickness of fiber composite parts). In this report, the potentials and limits ofregion-of-interest computed tomography are discussed with regard to spatial resolution and precisionwhen evaluating defects and local fiber orientation in squeeze cast components. The micro computedtomography scanner metRIC at Fraunhofer‘s Development Center X-ray Technology EZRT deliversregion-of-interest computed tomography up to a spatial resolution of 2 μm/voxel, which is sufficientfor determining the orientation of natural or synthetic fibers, wood, carbon and glass. The mean localfiber orientation is estimated on an isotropic structuring element of approximately 0.1 mm length bymeans of volume image analysis (MAVI software package by Fraunhofer ITWM). Knowing the exactlocal fiber orientation is critical for estimating anisotropic thermal conductivity and materials strength.

Nanoscale Structural and Mechanical Characterization of Nanowire-Reinforced Polymer Composites

2011 ◽  
Author(s):  
Wyatt Leininger ◽  
Xinnan Wang ◽  
X. W. Tangpong ◽  
Marshall McNea
Keyword(s):  
Elastic Modulus ◽  
Tensile Testing ◽  
Mechanical Characterization ◽  
Tensile Load ◽  
Small Strain ◽  
Epoxy Composites ◽  
Atomic Force ◽  
Reinforced Polymer ◽  
Multi Walled Carbon Nanotube

In this study, the mechanical properties of multi-walled carbon nanotube (MWCNT) reinforced epoxy composites were characterized using an in-house designed micro/nano tensile load stage in conjunction with an atomic force microscope (AFM). The surface of the nanocomposite was scanned by the AFM during intermittent tensile testing. Micro/nano deformation was observed, and the reinforcing mechanisms were discussed in conjunction with architecture and elastic modulus. Results show that the MWCNT reinforced nanocomposite has an increased elastic modulus. The Halpin-Tsai and Hui-Shia models were compared to the experimental results, and the Halpin-Tsai was found to correlate when only the load bearing outer layer of the MWCNTs were considered. Additionally, it is concluded that the combination of the load stage and AFM is capable of capturing insitu deformation progress for small strain increments.

Dynamic imaging of skeletal muscle contraction in three orthogonal directions

2010 ◽  
Vol 109 (3) ◽  
pp. 906-915 ◽  
Author(s):  
Richard G. P. Lopata ◽  
Johannes P. van Dijk ◽  
Sigrid Pillen ◽  
Maartje M. Nillesen ◽  
Huub Maas ◽  
...  
Keyword(s):  
Muscle Contraction ◽  
Biceps Brachii ◽  
Estimation Method ◽  
Vertical Direction ◽  
Local Strain ◽  
Local Deformation ◽  
Voluntary Contraction ◽  
Dynamic Imaging ◽  
Relative Deformation ◽  
Voluntary Contractions

In this study, a multidimensional strain estimation method using biplane ultrasound is presented to assess local relative deformation (i.e., local strain) in three orthogonal directions in skeletal muscles during induced and voluntary contractions. The method was tested in the musculus biceps brachii of five healthy subjects for three different types of muscle contraction: 1) excitation of the muscle with a single electrical pulse via the musculocutaneous nerve, resulting in a so-called “twitch” contraction; 2) a train of five pulses at 10 Hz and 20 Hz, respectively, to obtain a submaximum tetanic contraction; and 3) voluntary contractions at 30, 60, and 100% of maximum contraction force. Results show that biplane ultrasound strain imaging is feasible. The method yielded adequate performance using the radio frequency data in tracking the tissue motion and enabled the measurement of local deformation in both the vertical direction (orthogonal to the arm) and in the horizontal directions (parallel and perpendicular to direction of the arm) in two orthogonal cross sections of the muscle. The twitch experiments appeared to be reproducible in all three directions, and high strains in vertical (25 to 30%) and horizontal (−20% to −10%) directions were measured. Visual inspection of both the ultrasound data, as well as the strain data, revealed a relaxation that was significantly slower than the force decay. The pulse train experiments nicely illustrated the performance of our technique: 1) similar patterns of force and strain waveforms were found; and 2) each stimulation frequency yielded a different strain pattern, e.g., peak vertical strain was 40% during 10-Hz stimulation and 60% during 20-Hz stimulation. The voluntary contraction patterns were found to be both practically feasible and reproducible, which will enable muscles and more natural contraction patterns to be examined without the need of electrical stimulation.

A Novel Micro Tensile Testing Instrument with Replaceable Testing Specimen by Parylene Passivation Technique

2007 ◽  
Vol 1052 ◽  
Author(s):  
Yung-Dong Lau ◽  
Tso-Chi Chang ◽  
Hong Hocheng ◽  
Rongshun Chen ◽  
Weileun Fang
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Young’S Modulus ◽  
Tensile Testing ◽  
Test Specimen ◽  
Young's Modulus ◽  
Tensile Load ◽  
Thermal Actuator ◽  
Testing Instrument ◽  
Testing Specimen

AbstractThis study has successfully demonstrated a novel tensile testing approach to mount the thin film test specimen onto the MEMS instrument using microfabrication process. The MEMS instrument consists of thermal actuator, differential capacitance sensor, supporting spring. The thermal actuator applies tensile load on the test specimen to characterize the Young's modulus and the residual stress of thin films. As compare with the existing approaches, the problems and difficulties resulting from the alignment and assembly of thin film test specimens with the testing instrument can be prevented. Furthermore, the parylene passivation technique of MEMS fabrication process allows the changing of testing film materials easily. In application, the present approach has been employed to determine the Young's modulus and the residual stress of Al films.

Determination of Tensile Properties of Hemp-Fiber Bundle by Using Tensile Testing Equipment with Raspberry Pi

2014 ◽  
Vol 931-932 ◽  
pp. 1308-1312
Author(s):  
Paiboon Limpitipanich ◽  
Anucha Promwungkwa
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Fiber Bundle ◽  
Tensile Testing ◽  
Credit Card ◽  
Testing Machine ◽  
Tensile Load ◽  
Testing Equipment ◽  
Raspberry Pi ◽  
Hemp Fiber

Tensile strength of some natural fibers such as hemp is higher than that of steel. To determine tensile properties of hemp fiber, a fiber or bundle is tensile tested with universal testing machine that is controlled by personal computer. This paper presents a small tensile testing equipment that is controlled by Raspberry Pi (RPi), a credit-card-sized single-board computer. General Purpose Input Output (GPIO) pins on RPi were used for controlling the machine crosshead and receiving the tensile load that apply to a hemp bundle. A stepper motor was used to drive the crosshead. Tensile load was measured by using a load measurement system included load-cell, instrument amplifier, and analog-to-digital converter. The applied load and extension were real-time displayed and continuously recorded throughout the test. Testing hemp-fiber bundles with the proposed equipment found that their tensile strength and Youngs modulus were 446.75±184.36 MPa and 18.23±8.26 GPa, respectively. These results were in good agreement with the properties founded in other publications. Test results also found that hemp-fiber bundle with smaller diameter showed higher tensile strength than that of larger one.

A Novel Micro Tensile Testing Instrument With Replaceable Testing Specimen of Gold and Aluminum by Parylene Passivation Technique

2008 ◽  
Author(s):  
Yung-Dong Lau ◽  
Hong Hocheng ◽  
Rongshun Chen ◽  
Weileun Fang
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Young’S Modulus ◽  
Tensile Testing ◽  
Test Specimen ◽  
Young's Modulus ◽  
Tensile Load ◽  
Thermal Actuator ◽  
Testing Instrument ◽  
Testing Specimen

This study has successfully demonstrated a novel tensile testing approach to mount a thin film test specimen onto a MEMS instrument using microfabrication processes. The MEMS instrument consists of a thermal actuator, differential capacitance sensor, and supporting spring. The thermal actuator applies a tensile load on the test specimen to characterize the Young’s modulus and the residual stress of the thin film. As compare with the existing approaches, the problems and difficulties resulting from the alignment and assembly of a thin film test specimen with the testing instrument can be prevented. Furthermore, the parylene passivation technique with the MEMS fabrication process allows the user to change the test materials easily. In application, the present approach has been employed to determine the Young’s modulus and the residual stress of Au and Al films.

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