The Analysis of Bearing Capacity of Axially Compressed Cold Formed Steel Members

This paper presents a calculation method for axially compressed cold formed stainless, high strength and carbon steel profiles. Results of different authors in this field published in international journals depict current trends in this field. Paper also presents author’s numerical and experimental analysis of cold-formed centrally compressed elements. Numerical analysis was carried out by finite element method and program for the nonlinear static and dynamic structural analysis - PAK. The results obtained by experimental and numerical methods included boundary conditions, maximum force, buckling curve etc. Small difference observed in the values obtained by these different methods. Results werw compared to values predicted by international designing code in order to analyze if they are too conservative for cold formed steel sections

Application and mode of operation of non-contact stereometric measuring system of biomaterials

Nove optičke stereometrijske metode postaju uobičajene u praćenju mehaničkih karakteristika biomaterijala. Razumevanje mehaničkih karakteristika tvrdih i mekih tkiva je od velike važnosti u dizajniranju i ispitivanju biomaterijala. Mehaničko ponašanje biomaterijala se može proceniti korišćenjem brojnih metoda koje su zasnovane na kontaktnom ili bezkontaktnom merenju deformacija. Merenje deformacionog polja je u ovom radu izvršeno pomoću sistema za trodimenzionalno merenje deformacija i softvera Aramis. Sistem koristi dve digitalne kamere koje omogućavaju stereo prikaz uzorka, a u rezultatima se dobija kompletno deformaciono polje. Prikazano je nekoliko primera koji ističu korišćenje sistema u oblasti biomaterijala i pokazano je da ova metoda merenja može da isprati nove trendove eksperimenata.New optical stereometric methods are becoming commonplace in investigations of mechanical behaviour of biomaterials. An understanding of the mechanical behaviour of hard and soft tissues is of great importance in the design and investigation of biomaterials. The mechanical behaviour of biomaterials can be evaluated using a number of methods that are based on either contact or non-contact schemes for displacement measurement. The method for full-field measurement of strain is done by using the ARAMIS three-dimensional image correlation system. The system uses two digital cameras that provide a synchronized stereo view of the specimen and the results show the complete strain field during the tests. Several examples are presented that highlight the use of stereometric measuring system for modern biomaterials. It is shown that this measuring methodology can capture the trends of the experiments

The effect of input energy on toughness of weld metal made by gas metal arc welding of microalloyed steel

Instrumentiranim Šarpijevim klatno je ispitana udarna žilavost metala šava dva valjana mikrolegirana čelika, zavarena elektrolučno u zaštiti mešavine gasova. Prethodno određena optimalna mešavina gasova (Ar+5%CO2+0.9%O2) je korišćena sa različitim vrednostima unete energije da bi se odredio njen uticaj na žilavost metala šava na različitim temperaturama. Optimalne vrednosti unete energije su određene za oba čelika, koje su davale najveću energiju rasta prsline u prisustvu acikularnog ferita, kao dominantne mikrostrukture.Impact toughness of weld metals of two hot rolled microalloyed steels, welded by gas shielded metal arc process, has been evaluated by using the instrumented Charpy pendulum. Previously determined optimum gas mixture (Ar+5%CO2+0.9%O2) was used with different energy inputs to determine its effect on weld metal toughness at different testing temperatures. For both steels the optimum energy input has been determined, providing maximum crack propagation energy due to presence of acicular ferrite, as a dominant microstructure

The effect of input energy on toughness of weld metal made by gas metal arc welding of microalloyed steel

Instrumentiranim Šarpijevim klatno je ispitana udarna žilavost metala šava dva valjana mikrolegirana čelika, zavarena elektrolučno u zaštiti mešavine gasova. Prethodno određena optimalna mešavina gasova (Ar+5%CO2+0.9%O2) je korišćena sa različitim vrednostima unete energije da bi se odredio njen uticaj na žilavost metala šava na različitim temperaturama. Optimalne vrednosti unete energije su određene za oba čelika, koje su davale najveću energiju rasta prsline u prisustvu acikularnog ferita, kao dominantne mikrostrukture.Impact toughness of weld metals of two hot rolled microalloyed steels, welded by gas shielded metal arc process, has been evaluated by using the instrumented Charpy pendulum. Previously determined optimum gas mixture (Ar+5%CO2+0.9%O2) was used with different energy inputs to determine its effect on weld metal toughness at different testing temperatures. For both steels the optimum energy input has been determined, providing maximum crack propagation energy due to presence of acicular ferrite, as a dominant microstructure

Application and mode of operation of non-contact stereometric measuring system of biomaterials

Nove optičke stereometrijske metode postaju uobičajene u praćenju mehaničkih karakteristika biomaterijala. Razumevanje mehaničkih karakteristika tvrdih i mekih tkiva je od velike važnosti u dizajniranju i ispitivanju biomaterijala. Mehaničko ponašanje biomaterijala se može proceniti korišćenjem brojnih metoda koje su zasnovane na kontaktnom ili bezkontaktnom merenju deformacija. Merenje deformacionog polja je u ovom radu izvršeno pomoću sistema za trodimenzionalno merenje deformacija i softvera Aramis. Sistem koristi dve digitalne kamere koje omogućavaju stereo prikaz uzorka, a u rezultatima se dobija kompletno deformaciono polje. Prikazano je nekoliko primera koji ističu korišćenje sistema u oblasti biomaterijala i pokazano je da ova metoda merenja može da isprati nove trendove eksperimenata.New optical stereometric methods are becoming commonplace in investigations of mechanical behaviour of biomaterials. An understanding of the mechanical behaviour of hard and soft tissues is of great importance in the design and investigation of biomaterials. The mechanical behaviour of biomaterials can be evaluated using a number of methods that are based on either contact or non-contact schemes for displacement measurement. The method for full-field measurement of strain is done by using the ARAMIS three-dimensional image correlation system. The system uses two digital cameras that provide a synchronized stereo view of the specimen and the results show the complete strain field during the tests. Several examples are presented that highlight the use of stereometric measuring system for modern biomaterials. It is shown that this measuring methodology can capture the trends of the experiments

Novel procedure to determine actual stress-strain curves

This paper presents a novel procedure for determining the actual stress- strain curves for undermatching rectangular welded joints made of martensitic armoured steel Armox 500T. The method is based on an analytical expression for true stress; digital image correlation (DIC) with two cameras, i.e. recording 3D deformations of samples; and finite element method (FEM) for stress state analysis of samples. Stresses obtained by dividing the force by the current cross-sectional area of the sample do not represent the actual stress occurring in the sample, because they do not take into account the stress concentration. In this paper we have analysed the stress concentration obtained numerically using Abaqus software in which the model's entered strain values are measured by DIC method

Novel procedure to determine actual stress-strain curves

This paper presents a novel procedure for determining the actual stress- strain curves for undermatching rectangular welded joints made of martensitic armoured steel Armox 500T. The method is based on an analytical expression for true stress; digital image correlation (DIC) with two cameras, i.e. recording 3D deformations of samples; and finite element method (FEM) for stress state analysis of samples. Stresses obtained by dividing the force by the current cross-sectional area of the sample do not represent the actual stress occurring in the sample, because they do not take into account the stress concentration. In this paper we have analysed the stress concentration obtained numerically using Abaqus software in which the model's entered strain values are measured by DIC method

The effect of welding heat input on the weld metal toughness of microalloyed steels

Žilavost metala šava, jedan od kriterijuma prihvatljivosti zavarenog spoja, zavisi od količine unete toplote. Udarna žilavost metala šava dva toplo valjana mikrolegirana čelika, zavarena elektrolučnim postupkom u zaštiti mešavine gasova (Ar + 5% CO2+0,91% O2) je ispitana merenjem energije loma na instrumentiranom Šarpijevom klatnu. Utvrđeno je da je količina unete toplote od 7 kJ/cm optimalna za žilavost metala šava oba ispitivana čelika. Energija rasta prsline, kao bitna za žilavost metala šava, je za ovu količinu unete toplote veća od kritične, pa se ovako zavareni spoj može preporučiti za konstrukcije koje rade na niskim temperaturama.Weld metal toughness, one of weldment acceptability criteria, depends on heat input. Weld metal impact toughness of two hot rolled microalloyed steels, welded by electric arc with mixture gases shielding (Ar + 5% CO2+0,91% O2) is tested by measuring impact energy on instrumented Charpy pendulum. It has been found that heat input of 7 kJ/cm is optimal for weld metal toughness of both investigated steels. Crack growth energy, as substantial for weld metal toughness, is for this heat input higher than critical, and welded joint, produced in this way, can be recommended for manufacturing of welded structures for low temperature application