Analysis of shear strength of joints

Analiza spojeva opterećenih na smicanje započeta je teorijskim postavkama. Definiran je posmik i njegova pripadajuća posmična ravnina. Izvedeni su izrazi za veličine kojima se element odupire deformacijama prilikom smicanja i izrazi za potencijalnu energiju deformacije koja bi bila utrošena prilikom njezinog nastanka. Prikazan je model djelovanja sila koje rezultiraju ne- jednolikom pojavom posmičnih naprezanja u elementu. Takav raspored nejednolikog napreza- nja zbog lakšeg proračuna pojednostavljujemo i uzimamo njegovu srednju vrijednost, koja je korištena i u izvodu za uvjet čvrstoće. Nadalje, posmična naprezanja najčešće se javljaju u elementima kojima spajamo dijelove kon- strukcija. Elementi drvenih konstrukcija mogu biti spajani vijcima, dok elementi metalnih konstrukcija mogu biti spajani vijcima i zavarivanjem. Neovisno o vrsti spojeva, spojevi trebaju pravilno i kontinuirano prenijeti sile s jednog elementa na drugi. Navedene su prednosti i mane te podjele pojedinih spojeva kojima je olakšan odabir ovisno o potrebama. Za već spomenute spojeve elemenata izvedene su osnovne postavke proračuna i objedinjene numeričkim primjerima. Navedeni su primjeri proračuna za spojeve vijcima u otpornosti materijala te u metalnim i drvenim konstrukcija. Primjeri za zavarivanje dani su za metalne konstrukcije i u okviru otpornosti materijala.The analysis of joints loaded onto a shear lies on theoretical assupmtions. The shear and its associated shearing plane are defined. Expressions for the quantities by which the element resists deformations during shear and expressions for the potential strain energy that would be expended during its occurrence are derived. A model of the action of force resulting in an uneven occurence of shear strains in an element is shown. Such distribution of uneven straining for ease of calculation we simplify and tak its mean value, which is also used in the derivative for the strength condition. Furthermore, shear strains most often occur in the elements that connect parts of the structure. Elements of wooden structures can be connected with screws, while the elements of metal struc- tures can be connected with screws and welding. Regardless of the type of joints, joints need to correctly and continuously transfer forces from one element to another. Advantages and di- sadvantages, as well as the divisions of individual joints that makes the selection easier depen- ding on the needs, are listed. The basic calculation settings for the aforementioned element joints were performed and they are combined with numerical examples. We gave examples of calculations for joints with screws in the resistance of materials and in metal and wooden stru- cutres. Examples of welding are given for metal structures and within resistance of materials