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Castellated and cellular beams achieved the same strength as solid I-beams with the same depth, resulting in significantly lighter and more economical structures. The purpose of this study is to analyse the bending behaviour of I-beam steel sections with certain web openings by finite element analysis.

The accuracy of finite element results allows extensive numerical analysis of sections with web openings, concentrating on the web opening sizes and web opening positions. These assumptions can increase the induced section load with various shapes of web opening depth and web opening shapes of c-hexagon, hexagon, octagon, circular and square. This also includes spacing distances, with a 50-mm edge and 150-mm centre-to-centre distance and a section with a 100-mm edge and 200-mm centre-to-centre distance. Generally, the adjustment of the opening geometry (by reducing the angle of web pitch or reducing the opening depth depending on analysed parameters) may influence the bending behaviour.

Additionally, Model 2 was found to be the optimum model compared to Model 1, mainly in terms of bending. Moreover, the I-beam with a c-hexagon shape opening exhibited the lowest displacement compared to other sections with other web opening shapes. Section with a different arrangement of web opening, Type E shows the lower displacement while higher displacement is observed for Type A and also higher displacement considered for Type G. The optimum model is associated with Type E, followed by Type D, compared to other types of certain web opening and I-beam.

The use of sections with different arrangements of web opening improved the performance of the perforated section in terms of structural behaviour, compared to typical I-beam, thus leading to economic design.

The purpose of this work is to perform the finite element analysis (FEA) for the numerical discretization of sections with different arrangements of Web openings to investigate the torsion behavior. Typical hexagonal and circular Web opening sections are extensively used in steel construction due to economic development in building design. However, the use of sections with different arrangements of Web opening had improved the performance of the section with Web opening in terms of structural behavior which leads to economic design compared to typical I-beam.

The accuracy of FE results allows extensive numerical analysis of stress concentration magnitude for sections with Web openings, concentrating on the sizes and positions of the Web opening. Five shapes and three sizes of Web opening are used in this work. The shapes involved are c-hexagon, hexagon, octagon, circular and square, whereas the sizes of the Web opening involved are 0.67 D, 0.75 D and 0.80 D where D is the height of the Web. Two types of models for 200 × 100 × 8×6 mm steel section involved which is Model 1, where the section with 50 mm edge and 150 mm center-to-center distance and Model 2, where the section with 100 mm edge and 200 mm center-to-center distance.

It was found that these configurations affect the section with various shapes of Web openings sizes (0.67 D, 0.75 D, and 0.80 D). This also includes the spacing distances, with 50 mm edge and 150 mm center-to-center distance and also a section with 100 mm edge and 200 mm center-to-center distance. Through the FEA results of Model 1 and Model 2, it is found that 50% reduction in horizontal member length in hexagon Web opening, from 50 mm to 20 mm, caused increment about 30%–53% stress concentration in Web for c-hexagon. However, for a stress analysis of c-hexagon, geometry resulted in a lower stress concentration in the Web than other Web opening.

Additionally, the work emphasized the efficiency of Web opening shapes by using an appropriate Web opening radius in section with c-hexagon, hexagon, octagon, square and circular shapes. The final results show the contribution of appropriate Web opening radius to increase the section torsional capacity. It is observed that the torsional capacity at certain loading condition and its angle of twist is analysed.

The purpose of this paper was to investigate and evaluate the influence of geometrical and structural design changes in order to reduce shear-lag and increase specific strength and stiffness of thin-walled composite I-beam wing spars.

A detailed FEM model of a cantilevered I-beam spar was used to investigate the influence of increased transition fillet radius and increased web sandwich core thickness on the shear-lag effect at different width to thickness ratios of flanges. Evaluation functions were used to assess specific strength and stiffness of different spar configurations.

Increased web core thickness has greater influence on normal stress distribution and the reduction of the shear-lag than fillet size. Additional weight of thicker core is not compensated enough through reduction of stress concentration. Increased transition fillet and web core thickness increase optimum flanges width to thickness ratio. Shear-lag reduces the strength of the spar more than the stiffness of the spar.

Findings in this study and detailed insight in the shear-lag effect are important for aircraft design when minimum weight of the airframe is of supreme importance.

This combined shear-lag and weight optimization study deals with composite I-beams and loads that are specific for aerospace engineering. This study does not only evaluate the shear-lag phenomena, but primarily analyses fine structural details in order to reduce it, and increases specific strength and stiffness of I-beam spars.

Due to the enormous increase in economic development, structural steel material gives an advantage for the construction of stadiums, factories, bridges and cities building design. The purpose of this study is to investigate the behaviour of bending, buckling and torsion for I-beam steel section with and without web opening using non-linear finite element analysis.

The control model was simulated via LUSAS software with the four main parameters which included opening size, layout, shape and orientation. The analysis used a constant beam span which is 3.5 m while the edge distance from the centre of the opening to the edge of the beam is kept constant at 250 mm at each end.

The analysis results show that the optimum opening size obtained is 0.65 D while optimum layout of opening is Layout 1 with nine web openings. Under bending behaviour, steel section with octagon shapes of web opening shows the highest yield load, yield moment and thus highest structural efficiency as compared to other shapes of openings. Besides, square shape of web opening has the highest structural efficiency under buckling behaviour. The lower buckling load and buckling moment contribute to the higher structural efficiency.

Further, the square web opening with counter clockwise has the highest structural efficiency under torsion behaviour.

It is generally known that the perforated section such as the castellated section is good to sustain distributed loads but inadequate to sustain highly concentrated loads. Therefore, it is possible to design the opening in a different arrangement of web opening to achieve section efficiency, thus improving the strength and torsional behaviour of the section with web opening. This study aims to focus on the finite element analysis of I-beam with and without openings in steel section dominated to lateral-torsional buckling behaviour.

In this work, the analysis of different sizes, shapes and arrangements of web opening is performed by using LUSAS application to conduct numerical analysis on lateral-torsional buckling behaviour. This involves three diameter sizes of web opening, five types of opening shapes and two criteria of the model.

The section with c-hexagon web opening was placed about 200-mm centre to centre and 100-mm edge distance, contribute to 7.26% increase of buckling capacity. For the section with 150-mm centre to centre and 50-mm edge distance, the occurrence of local buckling contributes to decrease of lateral buckling section capacity to 19.943 kNm, where pure lateral-torsional buckling mostly occurred because of prevented section. Besides that, the web opening diameter was also analysed. The web crippling was observed because of the increase of opening diameter from 0.67 to 0.80 D.

This contributes to a decrease in buckling capacity as figured in the contour of the deformed shape. For Model 1, an increase of buckling capacity (31.46%) is observed when the opening diameter are changed from 0.67 to 0.80 D.

This study aims to use carbon fiber-reinforced polymer (CFRP) laminates to strengthen the compression flange of structural I-beam so as to avoid local failure of compression flange and to take a load to its full capacity. Light weight beam (LB) 100 at 5.1 kg/m and LB 115 at 8.1 kg/m are used for this purpose. The compression flange of a beam is well prepared to ensure a rust-free surface so as to achieve proper bonding between the flange and fiber sheet to avoid de-bonding at the time of testing. A flange of the beam is strengthened using CFRP sheets applied to it with the help of adhesive. The beam with CFRP is cured in air for 48 h before testing. Experiments are performed in a loading frame of 100 T capacity. Results show that the load carrying capacity of the strengthened beam increased by 25-30 per cent compared to the control beam (non-strengthened), and the local failure of the compression flange due to the applied load is totally avoided. The elastic behavior of the strengthened beam is also increased compared to the non-strengthened beam, which gives a higher yield point.

Different methods exist for strengthening various structures. Use of CFRP appears to be an excellent solution. Vast research has been conducted on the use of CFRP for strengthening and retrofitting of steel structures. The load carrying capacities of steel beams can be increased by strengthening their compression flange by using CFRP and avoiding the local failure of beams at early stages.

The load carrying capacity of a beam strengthened with CFRP increased by 25-30 per cent compared to the non-strengthened beam. In addition, the elastic behavior of the strengthened beam is also improved.

The compression flange of the steel beam is strengthened using different layers of CFRP strips to avoid the local failure, and its deflection is observed using linear variable deformation transducer.

T-sections of carbon fibre-reinforced composites are prone to delamination because they lack reinforcement through their thicknesses. The purpose of this paper is to present the structural response of cost-effective laminated T-sections when subjected to various types of loads and impacts.

The core of the automated manufactured beams is analysed. Pull-off, flange tension, and flange bending were tested for specimens extracted from an I-beam. The failure processes for all of the specimens were investigated in detail, leading to the statistical evaluation of the failure modes.

A correlation is apparent between the impact damage energy and certain fracture patterns. These results can be used to assess damage tolerance when designing stiffeners, beams, and various complex structures. The increase in strength by 25 per cent was measured for the advanced stitching located in the web section for the flange tension test.

The resistance displayed by the T-sections toward impact damage was studied experimentally, as the literature describing this topic is limited. The prevalence of one fracture mode for higher impact energies shows a possible advantage of the cost-effective preforms for the damage tolerant philosophy.

This paper aims to present an effective sensing detection system based on fiber Bragg grating (FBG) sensing technology for protective barriers that have been effectively applied to intercept and stop rocks from falling onto railway tracks. . Determination of exact stress and deformation values during impact tests for key components of the protective barrier forms important criteria for quality control of these barriers. Monitoring changes in force along the protective barrier when deployed in field application allows for real-time disaster warning for collapse and falling rocks.

In this paper, we propose a monitoring strategy for key components of a protective barrier. During performance tests, dynamic force and strain were measured for the steel strands and supporting I-beam, respectively. Design of a special elastic structure for the force transducer based on finite element analysis and tensile tests has been discussed here. Two types of FBG force transducers were manufactured based on the elastic structure. Four FBG force transducers and four FBG strain sensors were used for impact verification testing of a new rigid protective barrier with a design protection level of 25 KJ.

Dynamic force and strain responses were obtained during an impact of free-falling block with a kinetic energy of 25 KJ.

The FBG monitoring scheme can be extremely valuable for optimized design of the barrier and can provide real-time disaster warning in regions of collapse and falling rocks.

Concrete is subjected to elevated temperature for short duration, long duration and cyclic heating on many occasions. The dramatic fire accidents/incidents have renewed the interest in the area of research on concrete subjected to elevated temperature. From the literature review it is found that the experimental data which simulate the conditions of structural elements in stressed conditions when exposed to fire are scarce. The work presents a study on the residual characteristics of R.C. beams subjected to elevated temperature under unstressed and stressed conditions. The R.C beams were of size 120mm×120mm×1500mm and designed with single and double reinforcement and referenced as Type I and Type II respectively. M20 grade of concrete was used in casting the beams. The temperatures were kept as 100°C, 200°C, 300°C, 400°C and 500°C and the duration of exposure was 4 hours. The specimens were cooled in air and the residual properties were tested by conducting two point bending test on R.C. beams and their behavioral parameters were studied in comparison with beams tested under normal (room) temperature conditions. The extent of damage suffered measured by the damage factor was about 32 % for Type I beams and about 48% for the Type II beams tested under unstressed test condition when exposed to 500°C; whereas it is to an extent of 33% for Type I beams and 49% for Type II beams in stressed test condition for the same exposed temperature. The degradation in initial stiffness was nearly 57% and 49% for Type I and Type II beams in unstressed test and 54% and 73% respectively for stressed test when exposed to 500°C. The degradation in stiffness at 50% of ultimate load was nearly 36% and 35% for Type I and Type II beams in unstressed test and 49% and 76.6% respectively for stressed test when exposed to 500°C. The ultimate load of R.C. beams tested in stressed condition were marginally 5% lower than the beams under unstressed test condition.

The comparative efficiency of three flat triangular shell elements is being assessed for analysing non‐linear behaviour of general shell structures. The bending formulation of the three elements is based on a discrete Kirchhoff model (namely the well‐known 3‐node DKT element and a new 6‐node DKTP element). The in‐plane behaviour is defined by constant (CST), linear (LST)and quadratic (QST) strain approximations. The super‐position of bending and membrane elements leads to the 3‐node DCT element (DKT plus CST), the 3‐node DQT element (DKT plus QST) and the 6‐node DLT element (DKTP plus LST). The geometrically non‐linear formulation is based on an approximate updated Lagrangian formulation (AULF) and the solution is obtained by using the Newton‐Raphson method with an automatic arc‐length control method. Illustrative examples include pre‐ and post‐buckling of different shell structures showing, in particular, some bifurcation points, large rotations and displacements and very important membrane‐bending coupling.