Summary Health monitoring of cables in civil engineering structures is a great challenge, because their integrity directly affects the safety of the whole structure. A magnetostrictive (MS) transducer‐based guided wave method for cable damage detection is presented in this study. A wave energy‐based method is proposed for damage localization and severity assessment. The wave energy transmission coefficient at the damage location is presented as a measure for the damage condition. Firstly, the wave dispersion properties were analyzed on a steel strand with seven helical wires using a semi‐analytical finite element (SAFE) method. Then, the selection of exciting frequency and design of the MS transducer were carried out based on the SAFE analysis results. Numerical and experimental studies were performed on multiple cases of wire breakage and corrosion using the pitch‐catch method. Time‐of‐flight information on the wave packets reflected from the damages was used for damage localizations, while wavelet coefficients were used to accurately analyze wave energy transmission and reflection. It has been found that the damage locations and damage conditions can be determined accurately using the proposed method.

Lap joints are commonly used in civil infrastructure and mechanical assembly structures. Detecting the connection status of bolts, particularly in the early stages of use, is critical for ensuring structural integrity. A shear horizontal (SH) guided wave-based bolt looseness detection method, excited by a magnetostrictive patch transducer (MPT), is presented in this paper. A normalised bolt-looseness index I nor BL was proposed based on the wave energy transmission theory by analysing the signals received at the transducer for the transmitted wave passing through the actual contact area and the transducer for the direct incoming wave. Numerical and experimental studies were conducted on a lap joint with four bolts. The relationship between the I nor BL and bolt loads was obtained, verifying the effectiveness of this method for detecting the extent of the bolt looseness under various bolt tightness states. The results also show that SH0 waves, excited by an MPT, have better detection capability than Lamb waves, when the surface of the lap joint is subjected to liquid medium such as water and professional paint for bridges.

In this article, the finite element method (FEM) using cohesive element is applied to predict the delamination behavior in laminated composite with double delaminations embedded in different depth positions under compressive load. In particular, compared with single delamination composites, the interaction between delaminations and the complicated propagation behavior are discussed. Furthermore, the study is focused on the significant effects of double delaminations on delamination buckling and growth behavior, such as the distance between double delaminations and the delaminations’ depth position.

Rice is a water intensive crop and soil water conditions affect rice yield and quality. However, there is limited research on the starch synthesis and accumulation of rice under different soil water conditions at different growth stages. Thus, a pot experiment was conducted to explore the effects of IR72 (indica) and Nanjing (NJ) 9108 (japonica) rice cultivars under flood-irrigated treatment (CK, 0 kPa), light water stress treatment (L, -20 ± 5 kPa), moderate water stress treatment (M, -40 ± 5 kPa) and severe water stress treatment (S, -60 ± 5 kPa) on the starch synthesis and accumulation and rice yield at booting stage (T1), flowering stage (T2) and filling stage (T3), respectively. Under LT treatment, the total soluble sugar and sucrose contents of both cultivars decreased while the amylose and total starch contents increased. Starch synthesis-related enzyme activities and their peak activities at mid-late growth stage increased as well. However, applying MT and ST treatments produced the opposite effects. The 1000-grain weight of both cultivars increased under LT treatment while the seed setting rate increased only under LT3 treatment. Compared with CK, water stress at booting stage decreased grain yield. The principal component analysis (PCA) showed that LT3 got the highest comprehensive score while ST1 got lowest for both cultivars. Furthermore, the comprehensive score of both cultivars under the same water stress treatment followed the trend of T3 > T2 > T1, and NJ 9108 had a better drought-resistant ability than IR72. Compared with CK, the grain yield under LT3 increased by 11.59% for IR72 and 16.01% for NJ 9108, respectively. Overall, these results suggested that light water stress at filling stage could be an effective method to enhance starch synthesis-related enzyme activities, promote starch synthesis and accumulation and increase grain yield.

Finite element method (FEM) using cohesive element is developed to predict delamination buckling and growth behavior in laminated composites with coexisting delaminations under compressive loading. It is shown that the buckling behavior of coexisting delaminations is far more complicated than single embedded delamination. In the course of delamination buckling and growth, a parametric study was carried out to investigate the influence of the distance between coexisting delaminations, delamination size and depth position of a series of composite plates. In particular, a three zone rule was put forwarded to define the interaction behavior between coexisting delaminations. Moreover, it is shown that the potential of delamination growth strongly depends on the distance between coexisting delaminations.