Tomasz Sadowski - Academia.edu (original) (raw)

Papers by Tomasz Sadowski

1.3. Z jakiego materiału wykonane są rurki układu pokazanego na rysunku 1.6, jeśli wiadomo, że pr... more 1.3. Z jakiego materiału wykonane są rurki układu pokazanego na rysunku 1.6, jeśli wiadomo, że przy obciążeniu Q=2T przemieszczenie wolnego końca wyniosło ∆l=1,2mm. Dane (wymiary poszczególnych segmentów I, II, III): l 1 =0,5m, D 1 =50mm, d 1 =45mm l 2 =1,0m, D 2 =45mm, d 2 =38mm l 3 =1,5m, D 3 =38mm, d 3 =30mm Odpowiedź: Rurki wykonano z miedzi. E [GPa] stal 210 miedź 115 aluminium 69 Rys. 1.6. 1.4. Obliczyć i porównać wartości jednostkowej sztywności rozciągania dwóch prętów przedstawionych na rysunku 1.7. Pręty wykonane są z tego samego materiału o module Younga E. Iloraz średnic jest równy α=d/D=0,8. Dla jakiej wartości α jednostkowe sztywności rozciągania obu prętów będą jednakowe? Odpowiedź: c 1 /c 2 =2,17, α=0,643. Rys.1.7. Jednostkową sztywność rozciągania określa się jako wartość siły potrzebnej do wywołania jednostkowego zwiększenia lub zmniejszenia długości pręta, czyli P c l = ∆ , ponieważ Pl l EA ∆ = , więc EA c l = 1.1. Pręty podtrzymujące elementy sztywne 1.5. Jednorodna sztywna belka AB o ciężarze Q utrzymywana jest w położeniu poziomym przez trzy pręty jak pokazuje Rys.1.8. Zaprojektować przekroje poprzeczne prętów 1, 2 i 3. Dane: Q=900 kN; k r =k c =120 MPa; α=60 0. Rys. 1.8 1.6. Sztywna nieważka belka AB utrzymywana jest przez trzy pręty. W węźle A tego układu zawieszono ciężar Q jak pokazuje Rys.1.9. Obliczyć wymagane przekroje poprzeczne prętów. Dane: Q=800 kN; k r =k c =160 MPa; α=30 0 ; β=60 0. Rys. 1.9. 1.7. Obliczyć przekrój poprzeczny pręta CD podtrzymującego jednorodną sztywną belkę AB o ciężarze Q i obciążoną na końcu siłą P jak pokazuje Rys.1.10. Dane: Q=20 kN; P=240 kN; l=5 m; a=4 m; α=30 0 ; k r =160 MPa. Rys. 1.10. 1.8. Dwie jednorodne sztywne belki AB i CD o ciężarze Q każda podtrzymywane są przez pręty AE i AF (Rys.1.11). Zaprojektować przekroje poprzeczne prętów i wybrać najbliższy dowolny kształtownik hutniczy spełniający te warunki wg PN. Obliczyć pionowe przemieszczenie punktu D. Dane: Q=40 kN; P=120 kN; l=2 m; k r =140 MPa; E=2⋅10 5 MPa. Rys. 1.11. Rys. 1.12. 1.9. Blok o ciężarze Q podparty jest prętami jak pokazuje Rys.1.12. Obliczyć przekroje poprzeczne prętów. Dane: Q=800 kN; l=1 m; α=30 0 ; k r =k c =160 MPa. 1.10. Zaprojektować pręty podtrzymujące jednorodny ciężar Q pokazany na Rys.1.13. Przyjąć pręty w postaci rur wg PN-EN 10210-2:2000. Obliczyć odchylenie od pionu ścianki AB. Dane: Q=600 kN; l=2 m; k r =k c =140 MPa; E=2⋅10 5 MPa. 1.11. Zaprojektować pręty utrzymujące pomost o ciężarze G pokazany na Rys.1.14. Dane: G=300 kN; a=1,6 m; b=80 cm; h=60 cm; c=50 cm; d=40 cm; k r =k c =160 MPa.

Materials

The increasing popularity of additive manufacturing technologies in the prototyping and building ... more The increasing popularity of additive manufacturing technologies in the prototyping and building industry requires the application of novel, improved composite materials. In this paper, we propose the use of a novel 3D printing cement-based composite material with natural, granulated cork, and additional reinforcement using a continuous polyethylene interlayer net combined with polypropylene fibre reinforcement. Our assessment of different physical and mechanical properties of the used materials during the 3D printing process and after curing verified the applicability of the new composite. The composite exhibited orthotropic properties, and the compressive toughness in the direction of layer stacking was lower than that perpendicular to it, by 29.8% without net reinforcement, 42.6% with net reinforcement, and 42.9% with net reinforcement and an additional freeze–thaw test. The use of the polymer net as a continuous reinforcement led to decreased compressive toughness, lowering it o...

Buildings, Feb 28, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Key Engineering Materials, 2014

The study focused mainly on one of the parameters of mount technology - tolerance for fitting the... more The study focused mainly on one of the parameters of mount technology - tolerance for fitting the rivet in the hole in riveted and hybrid (riveted adhesive) joints. The research included numerical simulations of double lap joints with four rivets arranged in two rows and subjected to uniaxial tension. Simulations were carried out in Abaqus both for the purely mechanical and the hybrid joints. The connections without clearance (neat-fit) and with clearance of 0.2 mm, as well as with interference of-0.2 mm. The presence of clearance in one of the holes in the hybrid joint causes a decrease in the capacity of the hybrid connection by about 15% in configuration 1 (Fig. 2). This decrease can be even higher (21%) in the worse clearance placement, i.e. in configuration 2 (Fig. 2). The study shows that the occurrence of clearance in the holes can lead to dangerous consequences, so it is recommended to use holes calibration or develop a special type of rivet.

Materialwissenschaft und Werkstofftechnik, 2013

ABSTRACT The aim of the paper is a numerical analysis of heat transfer in polycrystalline composi... more ABSTRACT The aim of the paper is a numerical analysis of heat transfer in polycrystalline composites, containing metallic or elastic interfaces, i.e. metal-ceramic composites (MCCs) or ceramic matrix composites (CMCs). An example of MCCs is a two-phase material composed of brittle grains WC joined by the plastic binder Co. The work focuses also on the description of the heat concentrations in composites due to temperature changes, taking into account the real material internal structure, which includes grain shapes and interfaces. Under thermal loading the heat transfer in MMCs is mainly through metallic interfaces, where the heat flux concentrations occur due to different thermal properties of both phases. They can cause also stress concentrations and act as sources of damage initiators at the binder/carbide grains interfaces. The different contents of the interphase between elastic grains were taken into account in the analysis, starting from the interfaces of the small thickness: 2-4 m and volume content approximately 10% (e.g. Co), to the higher values up to 30%. The major conclusion is the following: the volume content of the metallic phase (Co binder) and its architecture (spatial distribution) inside the material strongly influences the heat transfer through the composites.

Materials Research, 2004

Mechanical properties of alumina-zirconia 643 composites for ceramic abutments

Computational Materials Science, 2005

ABSTRACT The present contribution focuses on the problem of the mechanical response of a polycrys... more ABSTRACT The present contribution focuses on the problem of the mechanical response of a polycrystalline ceramic material containing intergranular layers. The internal structure of the material was modelled using eight-noded isotropic hexagonal finite elements to represent grains and interfaces. Two kinds of the material were analysed numerically. Both were made up of elastic grains, but in the first case the interface layers were elastic and had different properties in comparison to the grains. In the second case, the interphase had visco-plastic properties. The paper considers the influence of the initial heterogeneity of the material on the stress and displacement distribution inside the polycrystalline material subjected to uniaxial tension. One can observe local stress concentrations at the so-called “triple points” and on the surface of the material. These can act as cracks initiators. Additionally, the influence of the viscosity parameter of the interface material was investigated.

Composite Structures, 2009

Using the finite element code ABAQUS and the user-defined material utilities UMAT and UMATHT, a s... more Using the finite element code ABAQUS and the user-defined material utilities UMAT and UMATHT, a solid brick graded finite element is developed for three-dimensional (3D) modeling of free vibrations of thermally loaded functionally gradient material (FGM) sandwich plates. The mechanical and thermal material properties of the FGM sandwich plates are assumed to vary gradually in the thickness direction, according to a power-law fraction distribution. Benchmark problems are firstly considered to assess the performance and accuracy of the proposed 3D graded finite element. Comparisons with the reference solutions revealed high efficiency and good capabilities of the developed element for the 3D simulations of thermomechanical and vibration responses of FGM sandwich plates. Some parametric studies are carried out for the frequency analysis by varying the volume fraction profile and the temperature distribution across the plate thickness.

Archives of Metallurgy and Materials, Dec 1, 2015

Skew bendIng of aIrcraft fuSelage panelS wIth "l" and "c" StrIngerS mounted by hybrId joInt Ukośn... more Skew bendIng of aIrcraft fuSelage panelS wIth "l" and "c" StrIngerS mounted by hybrId joInt Ukośne zginanie poszycia samolotU z Usztywnieniami typU "l" i "c", mocowanymi za pomocą złącza hybrydowego A section of fuselage skin with dimension 30 x 200 mm was subjected to numerical study and loaded by skew bending (Fig. 3). The thickness of the skin was 0,6 mm, the length of a leg of an angle "L" profile stringer was 12 mm with 1mm thickness. The angle of inclination α of the load plane to the skin plane varies in the range from 10° to 90° with 10° increment. The elastic-plastic material model of D16T aluminum alloy was used in simulations of the fuselage skin as well as for "L" and "C" profile stringers. In the material model description damage of aluminum alloy was taken into account. An adhesive layer with thickness of 0,1mm was modeled using cohesive elements with the failure mode depending on the shear strength and the tensile strength. The paper presents a comparative analysis of the considered structural elements with application of the unsymmetrical "L" profile or the symmetrical "C" profile with the same cross section area. All numerical studies were performed in Abaqus program. Finally, one can conclude that the stiffness of the structural element with application of the symmetrical "C" profile stringer is stronger, whereas the mechanical response of both versions of the hybrid joint significantly depends on the angle of load inclination α.

Molecules/Molecules online/Molecules annual, Mar 5, 2024

Archives of Metallurgy and Materials

HIGH-VELOCITY IMPACT OF 2-PHASE WC/Co COMPOSITE PLATE-BEGINNING OF THE PROCESS 2-phase composites... more HIGH-VELOCITY IMPACT OF 2-PHASE WC/Co COMPOSITE PLATE-BEGINNING OF THE PROCESS 2-phase composites are often used for high demanding parts that can undergo impact loads. However, most of the papers on dynamic loading concerns layered composites. In our opinion, the impact loads are not considered thoroughly enough. Good examples of 2-phase composites are: (1) a WC/Co cermet or (2) a monolithic ceramic Al 2 O 3 /ZrO 2. The WC/Co cermet is often modelled as having ductile elasto-plastic Co matrix and ideally elastic WC grains. It is because of very high crushing resistivity of the WC. In this paper, we present an extension to earlier elaborated models ([44]) with the assumption of ideal elasticity of the grains. The new and general numerical model for high-velocity impact of the 2-phase composites is proposed. The idea of this novelty relies on the introduction of crushability of grains in the composite and thermo-mechanical coupling. The model allows for description of the dynamic response both composite polycrystals made of: (1) 2 different purely elastic phases (e.g. Al 2 O 3 /ZrO 2) or (2) one elastic phase and the second one plastic (e.g. cermet WC/Co), or (3) 2 elasto-plastic phases with different material properties and damage processes. In particular, the analysis was limited to the cases (2) and (3), i.e. we investigated the WC/Co polycrystal that impacted a rigid wall with the initial velocity equal to 50 m/s.

Molecules

The mechanical properties of ceramic–metal nanocomposites are greatly affected by the equivalent ... more The mechanical properties of ceramic–metal nanocomposites are greatly affected by the equivalent properties of the interface of materials. In this study, the effect of vacancy in SiC on the interdiffusion of SiC/Al interfaces is investigated using the molecular dynamics method. The SiC reinforcements exist in the whisker and particulate forms. To this end, cubic and hexagonal SiC lattice polytypes with the Si- and C-terminated interfaces with Al are considered as two samples of metal matrix nanocomposites. The average main and cross-interdiffusion coefficients are determined using a single diffusion couple for each system. The interdiffusion coefficients of the defective SiC/Al are compared with the defect-free SiC/Al system. The effects of temperature, annealing time, and vacancy on the self- and interdiffusion coefficients are investigated. It is found that the interdiffusion of Al in SiC increases with the increase in temperature, annealing time, and vacancy.

Composite Structures

The modern polycrystalline composite materials have a complex internal structure consisting of di... more The modern polycrystalline composite materials have a complex internal structure consisting of different phases and interfaces with random distribution. Relevant examples are Al 2 O 3 /ZrO 2 , i.e. alumina/zirconia composites, widely used as structural materials with applications ranging from aerospace to bio-engineering. Depending on the phases content and on the grain size a broad range of material characteristics, among which elastic constants, can be obtained. With the aim of characterizing this class of materials, we exploit a numerical Fast Statistical Homogenization Procedure (FSHP) in order to both estimate the size of the Representative Volume Elements (RVE) and the effective elastic properties, assuming a linear elastic material behaviour. The 2-D analyses are performed considering a microstructure inspired by images of real portions of the Al 2 O 3 /ZrO 2 composite obtained from a scanning electron microscope. The recent Virtual Element Method is used in combination with the FSHP approach to numerically solve boundary value problems. Different volume contents of phases are considered ranging from pure Alumina to pure zirconia. The results are useful to reliably characterize