Common Maintenance Problems Research Articles

Maintenance of low impact development facilities: A case study of pilot sponge cities in China

The concept low impact development (LID) has been provided for over five decades for achieving sustainable stormwater management. However, once installed, LID facilities often suffer from a lack of maintenance, resulting in impaired functionality and substantial wastage of financial resource. Since 2014, many LID facilities have been constructed in Chinese pilot sponge cities. However, to date, there is little knowledge about the post-construction status of these LID facilities. In response, we investigated the current status quo, common problems needing maintenance, and residents’ attitudes towards maintenance of LID facilities. The results showed that, among 467 bio-retention facilities in three surveyed pilot sponge cities, approximately one third of the bio-retention facilities were in a good state; However, more than one thirds are facing issues of decreasing vegetation coverage rate, a deteriorating vegetation growth situation, and the slight silting or blocking of water inlets or overflow ports. Thus, regular maintenance is necessary, but the starting maintenance time can go through in the fifth year after construction. Unfortunately, public participation on the maintenance would be difficult. Even those respondents who willing to pay for the maintenance fee or possessing previous knowledge exhibit reluctance to engage in maintenance practices. The paper provides decision makers with a comprehensive overview of the status quo and common maintenance problems associated with LID facilities in the Chinese pilot sponge cities. It can also equip governments with insights to effectively address maintenance and management issues related to LID facilities.

Submicron laser‐textured vents for self‐cleaning injection molds

AbstractClogging of venting slots in injection molds is a common maintenance problem caused by the degradation and the accumulation of gaseous and volatiles by‐products of polymer melting. In this work, the effect of laser‐induced periodic surface structures on the self‐cleaning properties of venting slots is investigated. The degradation of poly(ethylene terephthalate) (PET) over different surfaces is characterized by reproducing the mechanisms that occurs in mold cavities when the air is pushed through the venting channel. An imaging technique is developed for the quantification of the sediment that deposits on sample surfaces due to condensation of by‐products of PET melting. The experimental results indicate that the use of a multiscale texture minimizes the deposition of residues on the vent surface reducing it from 17.2 to 3.1%. A linear dependency between contact angle and clogging ratio indicates the efficacy of the model that explains vent self‐cleaning properties considering their wetting properties.

A novel grey prognostic model based on Markov process and grey incidence analysis for energy conversion equipment degradation

Maintenance strategy for energy conversion equipment degradation is now experiencing the transformation from fail-and-fix to predict-and-prevent due to the equipment complexity and the strict requirements for equipment reliability. Actually, the current situation of world class maintenance is providing never-before-seen opportunities and challenges for the maintenance specialists. For this problem, the essence is to optimize present PM (preventive maintenance) strategies, so as to avoid some common maintenance problems, such as insufficient proactive maintenance, frequent problem repetition, and unnecessary and conservative PM. Besides, accurate prognostic methodology is the core section of this optimization. Considering the data uncertainty and the requirements for long-term forecast, grey model serves as an attractive and effective prognostic model for equipment degradation prognosis. To compensate the limitation of traditional grey model resulting in the unfitness of fluctuant data, the Markov model is introduced into traditional grey model. In order to expand the dimension of the original data, the grey incidence model is adopted, so as to further employ the additional time series data similar to the target series. Then, the scheme of the novel grey prognostic model, based on the Markov process and the grey incidence analysis, is proposed. Finally, the fouling process of a gas turbine compressor is chosen as an instance to validate this novel model. In addition, the study has been conducted on the relationship between model parameters and the prognostic accuracy, and the best parameters for this case are suggested. Comparative study results of different prognostic models show that considering the prognostic accuracy and fluctuations, this novel model is better than some other prognostic models.

Common Defects on Floating Mosque: Tengku Tengah Zaharah Mosque, Kuala Ibai, Kuala Terengganu

As an emerging country, the construction industry is one of the factors to the development growth of the national economy. In Malaysia, there are various types of construction projects such as office buildings, housing, houses of worship, public and private institutions as well as the construction of infrastructure such as roads, drainage, landscaping and so on. The development is considered as an asset that must be protected in order to maintain the function of the development. Moreover, to emphasis on good asset management can reduce high operating costs and has helped many companies to improve efficiently in the face of recession. In addition, maintenance costs can be improved by taking into account, the condition of the building and report on the performance of building maintenance costs before a decision is made. Development of a wide range of defects is not a new scenario in Malaysia. Whether new or old, each is exposed to different types of defects. This paper is to discuss the common maintenance problems and building defects on civil and structural elements at the floating mosques buildings across Malaysia due to various factors. It will also provide opportunities to improve understanding of the building surveying profession in our country, namely to understand the scope and work as a building surveyor.

In-situ monitoring of fatigue crack growth using high frequency guided waves

The development of fatigue cracks at fastener holes represents a common maintenance problem for aircraft. High frequency guided ultrasonic waves allow for the monitoring of critical areas without direct access to the defect location. During cyclic loading of tensile, aluminum specimens fatigue crack growth at the side of a fastener hole was monitored. The changes in the energy ratio of the baseline subtracted reflected guided wave signal due to the fatigue damage were monitored from a stand-off distance using standard ultrasonic pulse–echo measurement equipment. Good sensitivity for the detection and monitoring of fatigue crack growth was found.

A Novel Design of Aircraft Fuel Tank Inspection Robot

Aircraft fuel tank leakage is a very common maintenance problem. A continuum robot is designed for troubleshooting of leaks for fuel tank which has strong constraints and is also explosive. The biomimetic robot with several flexible sections applies actuation redundancy through pulling its four independent driving cables to realize bending motion of two degrees of freedom (DOF). The forward kinematics about the relations of cables lengths, angles and tip coordinates of single section is established using projection curvature method and coordinates transformation method. The decoupled multi-section kinematics function is deduced based on the kinematics analysis of single section. Simulations of single section motion are presented. We demonstrate finally the correctness of kinematics method through prototype experiments. DOI: http://dx.doi.org/10.11591/telkomnika.v11i7.2814 Full Text: PDF

Some Common Maintenance Problems and Building Defects: Our Experiences

Abstract Poor and improper building maintenance will definitely cause more damages and costly repair works if left unattended. In Malaysia, buildings are built in accordance with British Standard and under strict supervision. Unfortunately the maintenance aspects of the building are still weak. Making it worse, sometimes building maintenance is perceived as merely about the mechanical and electrical system in the buildings without much consideration given to civil and structural elements. This non-research paper is to discuss the common maintenance problems and building defects on civil and structural elements at the Social Security Organisation (SOCSO) buildings across Malaysia due to various factors. Some common problems involving water proofing system, cracks, soil settlement are discussed in this paper. For instance, with tropical climate and average rainfall of 250 centimetres in a year, a good water proofing system is crucial for buildings with flat roof in Malaysia. However the performance of water proofing systems depend on many factors i.e. quality of the materials, the skill of workers, application methods, substrates condition, weather, maintenance, etc. Recent roof leakage incidents at numerous prestigious buildings such as parliament house, high court and other government buildings has sparked more awareness among the engineering fraternity on the importance of good and systematic building maintenance. With 34 office buildings throughout Malaysia, Property Division of SOCSO has been dealing with such problems regularly and would like to share them with other participants of this conference.

Design Bionic Structure and Analysis of Kinematics for Aircraft Fuel Tank Inspection Robot

Aircraft fuel tank leakage is a very common maintenance problem. A snake-like robotic detector was designed for troubleshooting leaks of fuel tank which has strong constraint and is also explosive. The robot has several flexible sections based on bionics, and it can achieve actuation redundancy by independently pulling its four driven cables to carry out a bending motion of two-degrees of freedom. A solution framework was established among the cables length, angle and tip coordinate of single section by projection curvature and coordinates transformation. The decoupled kinematics equation between the multi-sections was deduced based on the analysis of single-section kinematics. Finally the correctness of the kinematics method was demonstrated by prototype testing.

E-journals: the OhioLINK experience

This paper discusses the OhioLINK Electronic Journals Center which was first made available to users in April 1998. The paper includes usage data on the 2 years of operation as well as the design and philosophy behind the project. In addition, the paper explores research on what users want, how best to anchor the existence of full-text resources in the minds of researchers as well as common maintenance problems for electronic journals in the library online catalog.

Analysis of Flange Joints Under External Loads

Flange joint leakage is one of the common maintenance problems in refineries and chemical plants. This paper studies the effect of external loads on the strength and leakage behavior of flanged joints. Finite element and analytical methods are compared, and the proposed method is compared with leakage data. The common “equivalent pressure” method is shown to be very conservative, and a method of evaluating external loads is recommended.