1. Introduction
The combination of excessive urbanization and global climate change has exacerbated the escalation of natural disasters in magnitude, frequency, and severity in afflicted cities. The Guangdong–Hong Kong–Macao Greater Bay Area (GBA) is one of China’s most open and economically dynamic regions, characterized by rapid urbanization and a sharp growth in population within China’s coastal regions. The frequent human activities have jeopardized the region landform and accordingly relocated the population [
1]. Such combination has amplified the vulnerability of weaker communities to disasters, therefore leading to a significant portion of residents being exposed to disasters in the GBA. Additionally, due to global climate change, excessive rainfall and flooding pose year-round challenges to the region’s inhabitants [
2]. Natural catastrophes underscore the unpredictable nature of disasters, the scarcity of resources in affected areas, and the swift environmental transformations that exacerbate vulnerabilities [
3]. These calamities engender a rise in “environmental refugees”, individuals compelled to seek new habitats due to environmental degradation.
Considering these challenges, the necessity for disaster prevention products in afflicted cities becomes paramount. Such products provide safety, protection, emergency response, rescue, and recovery functions before, during, and after a disaster [
4]. The adoption of modular design in disaster prevention products has led to benefits such as reduced manufacturing costs, increased productivity, and lower energy consumption [
5], therefore enhancing the adaptability and promptness of these solutions. Modular design has therefore been widespread applied in various disaster prevention products, including earthquake emergency housing, flood protection walls, air purification, and domestic waste treatment.
However, limited research has concentrated on post-disaster prevention products [
6]. The current research emphasizes pre-disaster and disaster prevention products, neglecting the significance of post-disaster prevention products [
7]. Despite this, the existing research may also guide critical pathways for the optimization of post-disaster product designs in terms of environmental sustainability awareness [
8,
9], humanization and personalization [
10], ease of operation and maintenance difficulty [
11], traditional form and functionality [
12], and comfort and ergonomics [
13]. A new breed of post-disaster prevention products is urgently warranted to mitigate the impact of major natural disasters and safeguard lives and property.
Another gap is the absence of post-disaster prevention products incorporating the concept of modular design at multiple scales. While modular design can streamline transportation and manufacturing processes for disaster prevention products [
5], its integration into post-disaster solutions remains limited, lacking a holistic approach and struggling to balance individual design aspects with spatial allocation strategies at different scales [
14,
15]. The concept of module design can make the post-disaster products more extensively applicable and comprehensive at multiple scale.
Therefore, utilizing the design of the emergency disaster prevention inflatable cabin (EDPIC) in Zhuhai City as an empirical case, this study aims to: (i) formulate spatial strategies of post-disaster prevention products based on population density and disaster-affected areas; (ii) construct an objective decision-making model to prioritize key design elements and develop a disaster prevention product strategy using the concept of modular design; and (iii) discuss the mechanical performance of the EDPIC in earthquake-prone regions through numerical simulations across various scales.
5. Discussion
5.1. Analysis of Application Scenarios and Engineering Mechanical Characteristics
The mechanical performance of the EDPIC holds immense significance during design. Specifically, a critical scenario arises following an earthquake event in regions prone to seismic activities. In this scenario, residential buildings may collapse, necessitating the relocation of residents to emergency tents. However, secondary hazards, such as debris flows induced by rainfall, can cause severe damage to these temporary shelters. Due to precipitation in gullies or slopes, debris flows involve the transportation of substantial solid materials, including mud, rocks, and boulders. The impact forces exerted by debris flows surpass those of floods by a considerable margin.
Consequently, the lack of impact resistance in emergency tents, typically constructed from non-woven fabrics, becomes a pressing concern. In order to address this issue, substituting emergency tents with robust and impact-resistant EDPICs becomes imperative in these application scenarios. This strategic replacement ensures enhanced safety and protection for residents in areas susceptible to seismic activities and subsequent hazards like debris flows. (
Figure 15).
As illustrated in
Figure 16a, this study draws upon the physical model introduced by Bi et al. [
33,
34]. In this context, H
PIC = 100 m, α = 45°, and S
PIC varies at intervals of 30 m, 60 m, 90 m, 120 m, and 150 m. The primary focus of this investigation lies in the analysis of the impact force variations on the protective cabin at different distances.
Figure 16b depicts the three-dimensional discrete element model established in PFC3D, specifically addressing the mechanical characteristics following debris flow impact on its frontal surface. This model serves as theoretical guidance for the mechanical aspects of EDPIC design. The independent variable examined in this study is the distance of the EDPIC from the base of the slope, referred to as S
PIC, ranging from 30 m to 150 m, encompassing varying debris flow impact force patterns on the EDPIC. The granular size distribution and specific parameters for this debris flow are derived from the research findings of Zhou et al. [
35] (as shown in
Table 3).
According to
Figure 17, it is evident that prior to the 70th second, the debris flow velocity exhibits pulsating fluctuations over time. However, after the 70th second, the debris flow velocity displays a gradual decrease over time. Notably, when S
PIC = 150 m, the average velocity is relatively low, whereas for S
PIC = 30 m, the average velocity is higher, although the difference between them is not substantial.
Figure 18 illustrates the variation in debris flow impact on an EDPIC under different S
PIC conditions. As shown in
Figure 18a, when S
PIC is 30 m, the debris flow exerts a significant impact on the EDPIC, reaching up to 1.8 × 10
7 kN. With increasing S
PIC, the impact force gradually decreases. The impact force on the EDPIC generally follows a pattern of increasing with time and eventually stabilizing.
Figure 18b presents the trends in maximum impact force and average impact force with respect to S
PIC. It is evident that as S
PIC increases, both the average and maximum impact forces exhibit a gradual decrease. When S
PIC increases from 30 m to 150 m, the maximum impact force on the EDPIC decreases by approximately one order of magnitude, while the average impact force decreases by approximately two orders of magnitude.
Figure 18c provides a fitted function for the variation in maximum impact force with S
PIC. It reveals that the logarithmic function of impact force is linearly related to S
PIC. The specific fitting results are summarized in
Table 4. Consequently, this linear relationship allows for the approximate calculation of debris flow impact force based on the position of the EDPIC relative to the slope toe, thereby providing guidance for engineering design.
5.2. Strategies for Disaster Prevention Products and Management at Multiple Levels
This paper develops a comprehensive disaster prevention product strategy by integrating macro, meso, and micro research levels into a unified model. No previous studies have proposed such a holistic approach. Each research level offers distinct advantages, as detailed in
Table 5. While most studies focus on examining a single aspect or, at most, combining two, our approach leverages the strengths of all three levels.
In the research on disaster prevention products at a macro level, a geographic information system (GIS) is utilized to create detailed maps that visually represent various quantities. A GIS-based model could be used to characterize the affected areas and interpret both the hydro-geomorphic (trenches along barrier beaches, erosion, deposition, etc.) and hydraulic (urban streams along the streets, flow directions, flood extent) factors.
In the research on disaster prevention products at the meso level, the focus is on identifying and prioritizing the design needs of disaster prevention products. This level emphasizes the importance of understanding human and environmental needs to create products that are both effective and sustainable. Factors such as material selection, color, and shape are considered to ensure the products meet the users’ requirements while adhering to sustainability principles.
In the research on disaster prevention products at the micro level, the emphasis is on measuring the structural resistance of the product. The core functionality of disaster prevention products is closely related to user safety, necessitating rigorous testing and the evaluation of structural integrity. This level ensures that the products can withstand the specific conditions they are designed to mitigate, thereby providing reliable protection during disasters.
5.3. Limitations
This research acknowledges several limitations, including potential biases in user feedback, which may arise from the subjective nature of surveys and interviews. Additionally, the research design may have constraints related to the generalizability of findings due to the specific geographic focus on the GBA. To address these limitations, future research could expand the similar geographical environment and include more diverse geographic regions.
Applying the methodologies used in this study involves adapting the GIS and AHP frameworks to local contexts. For instance, spatial data collection should encompass local water systems, flood-prone areas, and population densities relevant to the new region. User needs exploration should involve engaging with local populations through tailored surveys and interviews, ensuring cultural and contextual relevance. In regions with different geographic and socio-economic characteristics, the criteria for AHP may need to be adjusted to reflect local priorities and conditions.
Compared with previous research results, this study confirms an innovative application of disaster prevention products in the post-disaster period. Studies in different geographic areas have also emphasized the necessity of aligning disaster prevention strategies with local needs and conditions. However, this study introduces novel insights into the application of GIS and AHP for optimizing product design and resource allocation, demonstrating that these tools can significantly enhance disaster preparedness and response strategies. These comparisons underscore the effectiveness of integrating spatial data analysis and hierarchical modeling to improve disaster prevention product designs, suggesting that similar approaches can be successfully applied in other regions prone to natural disasters.
6. Conclusions
This study introduces a comprehensive design approach progressing from macro to meso and then to micro levels, as illustrated in
Figure 19. At the macro level, GIS analysis is employed to delineate risk zones and formulate product distribution strategies. The meso-level design involves using the AHP method to select and design the basic structure and additional features of post-disaster emergency products. At the micro level, numerical simulations are conducted to assess the impact resistance of product materials.
Guided by the principles of green modularization and sustainable development and driven by core concepts of human care and safety in post-disaster product design, this study utilizes the GIS-AHP design method to explore the post-disaster needs of environmental refugees and devise strategies for emergency product design. Numerical simulations are then used to validate these design strategies. This holistic approach, from a global to a local perspective, holds practical significance for engineering design research.
Addressing the challenges faced by refugees affected by natural disasters is a crucial area of research. Consequently, this study focuses on developing emergency disaster protection products tailored explicitly for flood and inundation scenarios. By employing the AHP method within a GIS analytical framework, the study investigates the requirements of environmental refugees concerning the modular design of disaster products. Through a comprehensive process of user research, demand analysis, weight computations, and detailed analysis, the study identifies user requirements and formulates a product design strategy.
- (1)
A case study on post-disaster product design for flood refugees in Zhuhai was conducted. Utilizing GIS technology, the most affected areas were identified, leading to the development of a targeted spatial configuration strategy based on natural geography. This approach improved product efficacy and resulted in a more comprehensive overall strategy.
- (2)
By prioritizing user demands, the study applied the AHP method to quantify requirements and prioritize user needs, directly translating these into design recommendations. This explicit connection between user research findings and final product design ensured enhanced design efficiency and user satisfaction, with the product’s effectiveness verified. The research methodology and process, based on addressing natural disaster issues in the Greater Bay Area and utilizing the GIS-AHP analysis method, provide valuable insights for similar product research endeavors.
- (3)
Numerical simulations evaluated the protective efficacy of the EDPIC under debris flow impact conditions. As the distance between the EDPIC and the slope angle (SPIC) increased from 30 to 150 m, the maximum impact force significantly decreased, while the average impact force diminished by approximately two orders of magnitude. This analysis resulted in an empirical formula that can serve as a valuable reference for engineering design purposes.
- (4)
This study presents a novel and integrated approach to designing post-disaster emergency products, combining GIS, AHP, and numerical simulations. Key findings include the identification of effective spatial strategies for product placement, improved design efficiency and user satisfaction through the AHP method, and the validation of product efficacy under diverse conditions. The AHP approach was crucial in quantifying requirements and prioritizing user needs, ensuring a clear connection between user research findings and final product design.
- (5)
A significant contribution of this study is the development of a comprehensive disaster prevention product strategy by integrating macro, meso, and micro research levels into a unified model. At the macro level, GIS analysis helps identify and prioritize areas most in need of disaster prevention products. At the meso level, the AHP method is used to systematically evaluate and prioritize user needs and design features. At the micro level, numerical simulations provide detailed insights into the material properties and structural performance under various disaster scenarios. This multi-layered approach ensures that the design process is both thorough and adaptable, addressing the complex nature of disaster prevention comprehensively. This holistic approach, which combines spatial analysis, user-centered design, and technical validation, has not been proposed in previous studies on disaster prevention products. By integrating these research levels, the study not only enhances the effectiveness and relevance of the products but also sets a new standard for future research in this field.
Future research will extend this study in several meaningful ways to advance the field of disaster resilience and sustainable design.
First, the approach could be applied to the design of products for other types of natural disasters, such as earthquakes, hurricanes, and wildfires, to assess the generalizability and robustness of the design framework. By adapting the GIS-AHP methodology and numerical simulations to different disaster scenarios, researchers can identify commonalities and unique requirements across various types of emergencies.
Second, further refinement of the empirical models through more extensive field testing and real-world data collection is essential. Enhancing the accuracy and reliability of the design recommendations will ensure that they are applicable in diverse conditions. This could involve longitudinal studies and real-time monitoring of product performance during actual disaster events.
Third, incorporating advanced technologies like machine learning and the Internet of Things (IoT) could provide more dynamic and adaptive design solutions in real-time disaster scenarios. These technologies can enable predictive analytics and automated responses, thereby improving the responsiveness and effectiveness of disaster prevention products.
Fourth, interdisciplinary collaborations with social scientists, environmental experts, and policymakers are crucial. Such collaborations can enrich the design process by ensuring that the products meet broader social and environmental needs. This includes understanding the social dynamics and environmental impacts of disaster prevention strategies, as well as aligning product designs with policy frameworks and regulatory standards.
Additionally, the results of this study have significant implications for possible modifications or adjustments to existing standards or codes. The comprehensive disaster prevention product strategy developed here can inform updates to building codes, safety regulations, and disaster preparedness guidelines, ensuring that they incorporate the latest research findings and technological advancements.
Finally, while this case study focused on flood refugees in Zhuhai, the methodology and findings can be extrapolated to other countries and regions. By adapting the GIS-AHP framework to local contexts and disaster types, researchers and practitioners can develop tailored disaster prevention strategies that address specific regional needs and conditions.
These extensions will not only broaden the applicability of the study’s findings but also contribute significantly to the field of disaster resilience and sustainable design. By addressing the identified gaps and incorporating advanced technologies and interdisciplinary insights, future research can enhance the effectiveness and sustainability of disaster prevention products globally.