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Elevated temperature material properties are essential in predicting structural member's behavior in high-temperature exposures such as fire. Even though experimental methodologies are available to determine these properties, advanced equipment with high costs is required to perform those tests. Therefore, performing those experiments frequently is not feasible, and the development of numerical techniques is beneficial. A numerical technique is proposed in this study to determine the temperature-dependent thermal properties of the material using the fire test results based on the Artificial Neural Network (ANN)-based Finite Element (FE) model.

An ANN-based FE model was developed in the Matlab program to determine the elevated temperature thermal diffusivity, thermal conductivity and the product of specific heat and density of a material. The temperature distribution obtained from fire tests is fed to the ANN-based FE model and material properties are predicted to match the temperature distribution.

Elevated temperature thermal properties of normal-weight concrete (NWC), gypsum plasterboard and lightweight concrete were predicted using the developed model, and good agreement was observed with the actual material properties measured experimentally. The developed method could be utilized to determine any materials' elevated temperature material properties numerically with the adequate temperature distribution data obtained during a fire or heat transfer test.

Temperature-dependent material properties are important in predicting the behavior of structural elements exposed to fire. This research study developed a numerical technique utilizing ANN theories to determine elevated temperature thermal diffusivity, thermal conductivity and product of specific heat and density. Experimental methods are available to evaluate the material properties at high temperatures. However, these testing equipment are expensive and sophisticated; therefore, these equipment are not popular in laboratories causing a lack of high-temperature material properties for novel materials. However conducting a fire test to evaluate fire performance of any novel material is the common practice in the industry. ANN-based FE model developed in this study could utilize those fire testing results of the structural member (temperature distribution of the member throughout the fire tests) to predict the material's thermal properties.

Top-seat angle connection is known as one of the usual uncomplicated beam-to-column joints used in steel structures. This article investigates the fire performance of welded top-seat angle connections.

A finite element (FE) model, including nonlinear contact interactions, high-temperature properties of steel, and material and geometric nonlinearities was created for accomplishing the fire performance analysis. The FE model was verified by comparing its simulation results with test data. Using the verified model, 24 steel-framed top-seat angle connection assemblies are modeled. Parametric studies were performed employing the verified FE model to study the influence of critical factors on the performance of steel beams and their welded angle joints.

The results obtained from the parametric studies illustrate that decreasing the gap size and the top angle size and increasing the top angles thickness affect fire behavior of top-seat angle joints and decrease the beam deflection by about 16% at temperatures beyond 570 °C. Also, the fire-resistance rating of the beam with seat angle stiffener increases about 15%, compared to those with and without the web stiffener. The failure of the beam happens when the deflections become more than span/30 at temperatures beyond 576 °C. Results also show that load type, load ratio and axial stiffness levels significantly control the fire performance of the beam with top-seat angle connections in semi-rigid steel frames.

Development of design methodologies for these joints and connected beam in fire conditions is delayed by current building codes due to the lack of adequate understanding of fire behavior of steel beams with welded top-seat angle connections.

Drawing on legitimacy theory, this study aims to investigate whether the benefits of the external assurance process pass beyond the current period and help firms improve corporate social responsibility (CSR) performance in the subsequent periods. Furthermore, the authors examine whether corporate governance (CG) and firm visibility moderate the relationship between assurance and CSR performance.

The authors retrieved data from Thomson Reuters from 2002 to 2019 and executed a fixed-effects (FE) panel regression analysis. The country-level sample distribution includes 63 countries with 4,625 unique firms and 29,054 data points within these countries. The authors run several robustness tests using an alternative subsample, instrumental variable regression analysis, country-industry-year FE regression analysis, excluding the financial sector and including additional control variables and regression analysis based on propensity score matching.

The findings indicate that external assurance helps firms achieve greater CSR performance in the current period and the subsequent two periods following external assurance. However, external assurance exerts its strongest positive impact on CSR performance in the current period, and its influence extends, albeit at a weaker level, to the following two periods. Furthermore, the first moderation analysis reveals that governance structure helps firms translate the assurance process into the greater social performance but does not help to achieve higher environmental performance. The second moderation analysis reveals that firm visibility/size positively moderates between the assurance process and governance and social performance but not between the assurance process and environmental performance.

Despite the concurrent association between CSR performance and assurance being examined before, the lag-lead relationship is the novelty of the study to highlight the long-term effect of assurance on CSR performance. Besides, although the direct effect of both CG practices and firm visibility on CSR performance and the external assurance process has been investigated before, the authors extend the literature by examining the moderating effect of CG practices and firm visibility on the external assurance and CSR performance relationship. This provides a better explanation of the extent to which the effect of external assurance on CSR performance is constructed and conditioned by CG practices and firm visibility, thereby drawing attention to contingencies’ role in firms’ practices.

The purpose of this study is to contribute toward providing the main aspects of numerical modeling the fire behavior of steel structures with finite elements (FEs). The application of the method is presented for a characteristic case study comprising the series of large-scale fire door tests performed at the Danish Institute of Fire and Security Technology.

Following a general overview of current practices in structural fire engineering, the FE method is used to simulate the large-scale furnace tests on steel doors with thermal insulation exposed to standard fire.

The FE model is compared with the fire test results, achieving good agreement in terms of developed temperatures and deformations.

The numerical methodology and recommended practices for modeling the fire behavior of steel structures are presented, which can be used in support of performance-based fire design standards.

This study aimed to develop a method to calculate the mattress indentation for further estimating spinal alignment.

A universal indentation calculation model is derived based on the system theory, and the deformation characteristics of each component are analyzed by the finite element (FE) model of a partial air-spring mattress under the initial air pressure of 0.01–0.025 MPa. Finally, the calculation error of the model is verified.

The results indicate that the indentation calculation model could describe the stain of a mattress given the load and the constitutive model of each element. In addition, the FE model of a partial air-spring mattress can be used for further simulation analysis with an error of 1.47–3.42 mm. Furthermore, the deformation of the series system is mainly contributed by the air spring and the components directly in contact with it, while the top component is mainly deflection deformation. In addition, the error of the calculation model is 2.17–5.59 mm on the condition of 0.01–0.025 MPa, satisfying the engineering application. Finally, the supine spinal alignment is successfully extracted from the mattress indentation.

The limitation of this study is that it needs to verify the practicality of the indentation calculation model for the Bonnier spiral spring mattress. The main feature of the Bonnier spring mattress is that all springs are connected, so the mattress deflection and neighborhood effect are more significant than those of the air-spring mattress. Therefore, the applicability of the model needs to be tested. Moreover, it is worth further research to reduce the deformation error of each component.

As part of the series of studies on the intelligent air-spring mattress, the indentation-based evaluation method of spinal alignment in sleep postures will be studied for hardness and intelligent regulation based on this study.

The results of this research are ultimately used for the intelligent adjustment of air-spring mattresses, which automatically adjusts the hardness according to the user's sleep postures and spinal alignment, thus maintaining optimal spinal biomechanics. The successful application of this result could improve the sleep health of the general public.

Based on the series system theory, an indentation calculation model for mattresses with arbitrary structure is proposed, overcoming the dependence of parameters on materials and their combinations when fitting the Burgers model. Further, the spinal alignment in supine posture is extracted from the indentation, laying a theoretical foundation for further recognition and adjustment of the spinal alignment of the intelligent mattress.

This study aims to examine the effect of corporate social responsibility (CSR) adoption on differentiation and cost leadership strategies and how governance structure moderates this CSR–strategy relationship.

The study data were retrieved from Thomson Reuters for non-financial firms between 2013 and 2019, and a fixed-effects panel regression analysis was executed.

The results indicate that CSR fosters cost leadership strategy but weakens differentiation strategy. This result supports the value generation school for cost leaders but also confirms the agency theory perspective for differentiators. Moreover, the governance structure does not moderate the relationship between a firm's CSR engagement and its business strategy, which implies a lack of corporate policies that concurrently consider both its CSR investment and strategies.

The findings of this study imply that cost leaders can integrate CSR practices into their business strategy and use their CSR engagement to increase their competitive position by stimulating cost efficiency and creating greater turnover. On the contrary, for differentiators, there is a trade-off between environmental and social engagement and business strategies. Thus, they are advised to enrich their unique product development abilities through the integration of environmental and social practices and reinforce their competitive position by addressing stakeholders' interests. The practical implication of the moderation analysis is that there is no rooted corporate policy behind the connection between CSR and firm strategy for both cost leaders and differentiators, which constitutes a missing link.

The findings of this study are of critical importance for firms, offering justification for the integration of two vital perspectives: social and environmental sustainability and financial sustainability. The moderating effect of governance performance tests the upper echelon's role in maintaining both sustainability perspectives concurrently and strengthening the legitimacy of the firms in society. Although maintaining a business strategy is important for shareholders' interests, pursuing a social and environmental sustainability strategy is crucial for meeting the expectations of all stakeholders.

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 study is to investigate the association between sustainability reporting (SR) and firm value considering the moderating effect of audit committee (AC) quality and auditor tenure on this association.

The data for the study comprise 41,500 firm-year observations worldwide between 2007 and 2018 drawing on ten main sectors. The authors run a country-industry-year fixed effect regression and address endogeneity concerns with further methodologies.

First, the authors find that SR is significantly and positively associated with both firm value and industry-adjusted firm value. Further tests revealed that the baseline findings hold for SR assurance and the Global Reporting Initiative framework as well. Second, the moderation analysis outlined the significant moderating role that the AC assumes. More specifically, AC independence and expertise were found to strengthen the value relevance of SR. Third, the market also appreciates the moderation of auditor tenure in SR.

Investors appreciate greater corporate transparency which means that sustainability reports are likely to reduce information asymmetry and thereby agency conflicts. In addition, the moderation analyses imply that shareholders consider AC quality while they attach value to corporate sustainability reports. Hence, the structure of the auditing function appears to perform an implicit assurance role in the value relevance of sustainability reports. In line with these implications, corporations can review and re-design their auditing function and decide whether or not they will attest to sustainability reports given that AC independence and expertise and auditor tenure predict this decision.

The study highlights the audit function’s growing role beyond financial reporting and suggests implications for ACs and auditors in ensuring shareholders about the credibility of SR.

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.

The response of the Pine Flat dam–water–foundation rock system is studied by a new described approach (i.e. FE-(FE-TE)-FE). The initial part of study is focused on the time harmonic analysis. In this part, it is possible to compare the transfer functions against corresponding responses obtained by the FE-(FE-HE)-FE approach (referred to as exact method which employs a rigorous fluid hyper-element). Subsequently, the transient analysis is carried out. In that part, it is only possible to compare the results for low and high normalized reservoir length cases. Therefore, the sensitivity of results is controlled due to normalized reservoir length values.

In the present study, dynamic analysis of a typical concrete gravity dam–water–foundation rock system is formulated by the FE-(FE-TE)-FE approach. In this technique, dam and foundation rock are discretized by plane solid finite elements while, water domain near-field region is discretized by plane fluid finite elements. Moreover, the H-W (i.e. Hagstrom–Warburton) high-order condition is imposed at the reservoir truncation boundary. This task is formulated by employing a truncation element at that boundary. It is emphasized that reservoir far-field is excluded from the discretized model.

High orders of H-W condition, such as O5-5 considered herein, generate highly accurate responses for both possible excitations under both types of full reflective and absorptive reservoir bottom conditions. It is such that transfer functions are hardly distinguishable from corresponding exact responses obtained through the FE-(FE-HE)-FE approach in time harmonic analyses. This is controlled for both low and high normalized reservoir length cases (L/H = 1 and 3). Moreover, it can be claimed that transient analysis leads practically to exact results (in numerical sense) when one is employing high order H-W truncation element. In other words, the results are not sensitive to reservoir normalized length under these circumstances.

Dynamic analysis of concrete gravity dam–water–foundation rock systems is formulated by a new method. The salient aspect of the technique is that it utilizes H-W high-order condition at the truncation boundary. The method is discussed for all types of excitation and reservoir bottom conditions.