In situ and nondestructive characterization of mechanical properties of heritage stone masonry

2018 ◽  
Vol 77 (7) ◽  
Author(s):  
Edith Estefanía Orenday-Tapia ◽  
Jesús Pacheco-Martínez ◽  
Raudel Padilla-Ceniceros ◽  
Rubén Alfonso López-Doncel
Keyword(s):  
Mechanical Properties ◽  
Stone Masonry ◽  
Nondestructive Characterization

scholarly journals Experimental Evaluation of Shear Behavior of Stone Masonry Wall

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2313
Author(s):  
Maria Luisa Beconcini ◽  
Pietro Croce ◽  
Paolo Formichi ◽  
Filippo Landi ◽  
Benedetta Puccini
Keyword(s):  
Shear Behavior ◽  
Stone Masonry ◽  
Masonry Walls ◽  
Mechanical Parameters ◽  
In Situ Tests ◽  
Capacity Curves ◽  
Historical Structures ◽  
Definition Of

The evaluation of the shear behavior of masonry walls is a first fundamental step for the assessment of existing masonry structures in seismic zones. However, due to the complexity of modelling experimental behavior and the wide variety of masonry types characterizing historical structures, the definition of masonry’s mechanical behavior is still a critical issue. Since the possibility to perform in situ tests is very limited and often conflicting with the needs of preservation, the characterization of shear masonry behavior is generally based on reference values of mechanical properties provided in modern structural codes for recurrent masonry categories. In the paper, a combined test procedure for the experimental characterization of masonry mechanical parameters and the assessment of the shear behavior of masonry walls is presented together with the experimental results obtained on three stone masonry walls. The procedure consists of a combination of three different in situ tests to be performed on the investigated wall. First, a single flat jack test is executed to derive the normal compressive stress acting on the wall. Then a double flat jack test is carried out to estimate the elastic modulus. Finally, the proposed shear test is performed to derive the capacity curve and to estimate the shear modulus and the shear strength. The first results obtained in the experimental campaign carried out by the authors confirm the capability of the proposed methodology to assess the masonry mechanical parameters, reducing the uncertainty affecting the definition of capacity curves of walls and consequently the evaluation of seismic vulnerability of the investigated buildings.

Characterization of the Aniline.DBSA/Thermoplastic Polyurethane Blends for the Thermo-Mechanical and Electro-Mechanical Properties

2021 ◽  
Vol 875 ◽  
pp. 96-103
Author(s):  
Ayesha Afzal ◽  
Iqra Abdul Rashid ◽  
H.M. Faizan Shakir ◽  
Asra Tariq
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Polyurethane ◽  
Strain Sensors ◽  
Sem Images ◽  
Dynamic Mechanical Thermal Analyzer ◽  
Thermal Analyzer ◽  
Uniform Dispersion ◽  
Polymerization Method

Conducting polymer blends Polyaniline-Dodecylbenzene sulfonic acid (Pani.DBSA) and thermoplastic polyurethane (TPU) were prepared using in-situ emulsion polymerization method by dissolving both components in DMF. Ani.DBSA/TPU blends were prepared with different compositions 20/80, 30/70, 40/60 and 50/50 wt%. Theses blends have good conducting and mechanical properties. Blends were characterized by Potentiostate, Thermogravimetric analysis (TGA), Infrared spectroscopy (FTIR) and Dynamic mechanical thermal analyzer (DMTA). The electrical conductivity increases up to 30 wt% loading of aniline.DBSA after that it decreases gradually. The uniform dispersion of aniline.DBSA showed in SEM images which is the indication of a strong connection between aniline.DBSA and TPU which increase the conductivity. These blends can be used as strain sensors.

Preparation and Characterization of In Situ Nanocomposites of Graphene Nanosheets/Polyurethane

2019 ◽  
Vol 814 ◽  
pp. 90-95 ◽  
Author(s):  
Guang Lei Lv ◽  
Yuan Yuan Li ◽  
Chen Fei ◽  
Zhi Hao Shan ◽  
Jing Gan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Tensile Strength ◽  
Graphene Nanosheets ◽  
Graphene Sheets ◽  
Microstructural Properties ◽  
Wear Performance ◽  
Polyurethane Composites

Graphene nanosheets/polyurethane (GNS/PU) was prepared in situ by polymerization technique for the manufacture of PU safety shoes soles. The graphene nanosheets/polyurethane composites were characterized for their mechanical properties, thermal conductivity and abrasion resistance, and comparison is made with those of the neat polyurethane. The microstructural properties of GNS/PU were characterized by SEM. The results show that with the increase of the amount of graphene within the range of weight-percentages analyzed, the tensile strength of the composites gradually increases. The tensile strength of the GNS/PU composites increased to 64.14 MPa with 2 wt% GNS, compared with 55.1 MPa for neat PU. When the graphene sheets reached 2 wt%, the abrasion volume reached 71 mm3. Compared with the pure PU, the wear performance of GNS/PU composites was significantly improved.

A Novel In-Situ Nanoindentation Characterization of Phase Transforming Materials

2015 ◽  
Vol 1754 ◽  
pp. 19-24
Author(s):  
A. Alipour Skandani ◽  
R. Ctvrtlik ◽  
M. Al-Haik
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Creep Compliance ◽  
Physical And Mechanical Properties ◽  
In Situ Methods ◽  
Negative Creep ◽  
Nanoindentation Instrument ◽  
Structural Instabilities

ABSTRACTMaterials with different allotropes can undergo one or more phase transformations based on the changes in the thermodynamic states. Each phase is stable in a certain temperature/pressure range and can possess different physical and mechanical properties compared to the other phases. The majority of material characterizations have been carried out for materials under equilibrium conditions where the material is stabilized in a certain phase and a lesser portion is devoted for onset of transformation. Alternatively, in situ measurements can be utilized to characterize materials while undergoing phase transformation. However, most of the in situ methods are aimed at measuring the physical properties such as dielectric constant, thermal/electrical conductivity and optical properties. Changes in material dimensions associated with phase transformation, makes direct measurement of the mechanical properties very challenging if not impossible. In this study a novel non-isothermal nanoindentation technique is introduced to directly measure the mechanical properties such as stiffness and creep compliance of a material at the phase transformation point. Single crystal ferroelectric triglycine sulfate (TGS) was synthetized and tested with this method using a temperature controlled nanoindentation instrument. The results reveal that the material, at the transformation point, exhibits structural instabilities such as negative stiffness and negative creep compliance which is in agreement with the findings of published works on the composites with ferroelectric inclusions.

Mechanical Characterization of Polymer Nanowires Using MEMS

2006 ◽  
Author(s):  
B. A. Samuel ◽  
Bo Yi ◽  
R. Rajagopalan ◽  
H. C. Foley ◽  
M. A. Haque
Keyword(s):  
Mechanical Properties ◽  
Tensile Testing ◽  
Furfuryl Alcohol ◽  
Mechanical Characterization ◽  
Uniaxial Tensile ◽  
Testing Device ◽  
Uniaxial Tensile Testing ◽  
Polymer Nanowires

We present results on the mechanical properties of single freestanding poly-furfuryl alcohol (PFA) nanowires (aspect ratio > 50, diameters 100–300 nm) from experiments conducted using a MEMS-based uniaxial tensile testing device in-situ inside the SEM. The specimens tested were pyrolyzed PFA nanowires (pyrolyzed at 800° C).

Characterization of Mechanical Properties of Brittle Coating Systems by Various Indentation Techniques

2007 ◽  
Vol 352 ◽  
pp. 53-58
Author(s):  
Jong Ho Kim ◽  
Young Gu Kim ◽  
Hyeon Keun Lee ◽  
Do Kyung Kim
Keyword(s):  
Mechanical Properties ◽  
Thin Coating ◽  
Strength Measurement ◽  
Adhesion Properties ◽  
Brittle Coating ◽  
Transparent Substrate ◽  
Tin Coatings ◽  
Sic Coatings

The mechanical properties of brittle coating structures were characterized by various indentation techniques. The adhesion properties of the coatings were evaluated by in situ scratch and sphere indentation method. Physical vapor deposited TiN coatings on transparent substrates, sapphire, were scratched by diamond cone indenter and in situ observed through the transparent substrate. In situ scratch results reveal that the failure of coating is originated from the damage of the substrate and the plastic deformation of substrate is a primary factor for determining the adhesion breakage. The unique characterization technique for the strength measurement of brittle thin coating has been developed. The strength of the thin coating was evaluated by the sphere indentation on the trilayer structure. The CVD SiC coatings on graphite were characterized by the technique. It is concluded that the microstructure of SiC coatings influences the strength. In this paper, the various indentation technique were applied to evaluate the mechanical properties of TiN and SiC coatings and the effect of microstructure on the reliability of the brittle coating system was discussed.

Reinforcement from In-Situ Precipitated Silica in Polysiloxane Elastomers under Various Types of Deformation

1992 ◽  
Vol 274 ◽  
Author(s):  
James E. Mark ◽  
Shuhong Wang ◽  
Ping Xu ◽  
Jianye Wen
Keyword(s):  
Mechanical Properties ◽  
Uniaxial Elongation ◽  
Compression Set ◽  
Precipitated Silica ◽  
Equilibrium Swelling ◽  
Rupture Energy ◽  
End Linking ◽  
Reinforcing Effects

ABSTRACTElastomeric networks prepared by tetrafunctionally end linking hydroxyl-terminated poly(dimethylsiloxane) chains (PDMS) were filled by the in-situ precipitation of silica. The resulting networks were investigated under uniaxial elongation, biaxial extension, shear, and torsion in order to characterize the resulting changes in mechanical properties. Compared with the unfilled networks, the silica-filled materials showed large reinforcing effects. Specifically, their values of the modulus, ultimate strength, and rupture energy increased significantly. The results thus indicate that the PDMS networks filled by the in-situ precipitation of silica have very good mechanical properties in several, rather different deformations. Examples of other deformations of interest are equilibrium swelling, and dynamic cycling for characterization of compression set.

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